It was supposed to be an informational session about voter registration. But it quickly morphed into a Barack Obama revival meeting.

"It's here. It's on," former Pittsburgh City Councilman Sala Udin told a hushed gathering of mostly black political activists yesterday at the Hill House. "Pennsylvania may decide whether or not the next president of the United States is an African American. "

"As long as I've been involved in politics, I've never felt the kind of energy that this campaign has generated. Never."

Across Allegheny County yesterday morning, Obama supporters met in living rooms, libraries, shopping malls and coffee shops, eager to get to work.

Indeed, Mr. Obama, the Illinois senator, has sometimes been tagged as the candidate of the latte-sipping crowd, making it perhaps fitting that many of his volunteers ended up at Aldo's in Mt. Lebanon, Katerbean in Regent Square or the Starbucks in Ross or Gibsonia.

Everywhere, the marching orders were essentially the same: Register as many Democrats as possible before the March 24 deadline, preferably right on the spot.

There were slight variations. The Hill group focused on all voters, while in the North Hills, the target was independents.

"I want you to just go up and ask them what they think about the election," Shea McKinney, a volunteer organizer based in Ross, told the 16 volunteers who showed up at a Starbucks there. "If they say, 'I'm a big Barack supporter, I wish I could vote for him,' then you're going to transition into 'You know in Pa. you can still register to vote as a Democrat!' "

Mr. Obama has consistently trailed New York Sen. Hillary Rodham Clinton in polls in the Keystone State, but he's expected to run strongly among upper-income white Democrats and the large African-American communities in both Philadelphia and Pittsburgh on April 22.

"This is the first time that I can say with a very serious face to children -- African-American children -- that you can be president," Keith Murphy, executive director of the Bethany House Academy in St. Clair Village and Northview Heights said at the Hill House. "I'm going to work as hard as I can to get folks mobilized."

"It takes a lot to get me inspired about something," said Leon Clark, 66, of the Hill District. "I like Hillary Clinton, too, but the term 'change' really meant a lot to me."

Starting today, organizers plan to set up tables in black churches to register parishioners as they leave services. Mr. Udin yesterday warned them that they can wear Obama stickers, but any active campaigning for the candidate would run afoul of election laws.

After two hours of reviewing the finer points of voter registration forms and absentee ballot applications, the group of about 20 people headed out into yesterday's rainy, icy, snowy "wintry mix" to scout out new voters in the Hill District, the North Side, the Mon Valley and other parts of the county that have large black populations.

After the meeting, Gaye Velar, 57, of Rankin, braved a mixture of snow, sleet and general voter apathy as she went door-to-door in Crawford Square.

When she asked Joanne Fowler, 77, if she wanted to register, the answer was, "Not particularly."

"I don't like either of them," Ms. Fowler said.

Other potential voters weren't home. Some just weren't interested. Or they already planned to support Mr. Obama.

It took Ms. Velar about 45 minutes to find her first customer: Clarice Jones, 60.

"You're like my daughter. She's an Obama person," Ms. Jones said, adding with a laugh: "If I don't vote for Obama she'll kill me."

Meanwhile, in the cozy confines of the Ross Starbucks on McKnight Road, Alex Homol, 19, who was there with her friend Andrea Banovic, also 19, cited Mr. Obama's views on health care -- "his plan seems more affordable" -- while Ms. Banovic said she liked his message of change.

"What a bunch of bull," muttered Ron Brown, who was sitting in a nearby chair reading a newspaper column by conservative Charles Krauthammer. A more typical North Hills voter, he's a registered Republican who likes Sen. John McCain -- although he has fond memories of shaking John F. Kennedy's hand during a 1960 Pittsburgh campaign stop.

"Obama's a charlatan," he said in a low voice. "He's all talk. But I guess I can understand why some of these young people like him. Wasn't it Winston Churchill who said, 'If not liberal when you're young, you have no heart, and when you're not conservative when you're older, you have no brains'?"

It's not clear just how old the volunteers were at the Starbucks yesterday, but they represent the first building block of the Obama campaign's organization in this state. Actually, maybe the second building block: last weekend, Mr. Obama's campaign trained 1,981 people across the state in a "neighborhood leadership program."

This weekend, it was those newly trained leaders' turn to train volunteers to register voters.

Ross presents a bit of a conundrum for the Obama campaign: a classic "swing" district which went for Al Gore by a small margin in 2000 and for George W. Bush in 2004, it has 12,000 registered Democrats, 10,000 registered Republicans and about 2,800 independent voters.

A sizable number of voters here are older, which is good for Mrs. Clinton, said Mr. McKinney, but there are areas of opportunity.

"We're targeting a lot of rental units where people are unregistered and not canvassed as much," he said, noting that in the more affluent neighborhoods, in mostly Republican McCandless, for example, " if you're still a Democrat and living in a neighborhood like that, you probably may go for Obama."

Voter registration is a little trickier than it looks, he told the group. Don't argue, he warned them. Don't spend a lot of time chatting after you've registered a voter -- time is of a premium -- and most of all, be careful about line 4C on the registration form.

"It says municipality, but sometimes a voter may give you their mailing address, which is not necessarily the same thing," he said, suggesting they ask the voter what their police cars say, or where their municipal building is located.

More importantly, don't proselytize.

In January, paid Obama staffers began arriving in the state for their first big organizational task: a petition drive to field delegate slates in all 19 of the state's congressional districts by Feb. 21. Ultimately they fielded full slates in each district, something the Clinton campaign wasn't able to do.

But it was just a symbolic victory, since Mrs. Clinton will still be able to appoint a full complement of delegates, after the primary.

The Pittsburgh region has bested its neighbors in the eastern part of the state in an important way, he added: "netroots" campaigning. In 2004, online "Meetup" groups largely operated independently of campaigns, but this year the candidates have moved to embed those Internet-based social networks into their own Web sites.

At MyBarackObama.com, a voter can punch in a ZIP code or city and get a list of groups he or she can join to get details on local events, news stories and other information. The largest single "netroots" group is located in Pittsburgh -- "Pittsburgh, Pennsylvania for Obama" -- a group that's bigger than Philadelphia's or any other in the state, although the newly formed Pennsylvanians for Obama may replace it as the largest.

That volunteer strength, while potent, yielded perhaps fewer registrations yesterday than expected due to the weather -- one group of volunteers visited nearly 60 houses and got 5 people to register as Democrats, but in the end, 23 new Democrats were registered, which is a start, said Mr. McKinney, a firm believer in the "walk and talk" school of campaigning -- at least in the middle-to-lower middle-income neighborhoods in the southern part of Ross Township.

"The reason why the Democrats haven't done as well in elections is that we lost our grassroots," he said, as he maneuvered his car into North Hills Estates, a solid middle-class area with homes dating from the 1920s. "The committee system doesn't work their neighborhoods anymore and walk and talk with people, and that's what you need to have a healthy democracy, a little 'd' democracy."

A volunteer in both Al Gore and John Kerry's presidential campaigns, he said the Obama organization is far more decentralized. Instead of being called to a central location outside his neighborhood, Mr. McKinney said he was told, from the very beginning, to stick close to home.

"They haven't tried to overcontrol things," he said.

Still, Mr. McKinney only got one registration -- and it was a bit of a mixed victory. Joseph Wittkofski signed on, but his wife Denise is for Mrs. Clinton. "I just think Hillary Clinton would get more things done," Mrs. Wittkofski said, sitting on the staircase in her front hall.

"I'm concerned that Obama is more like Ronald Reagan," she added, as her husband looked on in mock horror," in the sense that there's a lot of rhetoric there. Actually, I'd love to see Hillary be president and Obama be vice president."

But in this mostly Republican neighborhood, "we don't talk politics to our neighbors," she added with a laugh.