Philadelphia ? Lefty radio debuted Wednesday, with comedian Al Franken declaring war on Bill O’Reilly, Rush Limbaugh and the Bush administration from a broadcast studio “3,500 feet below Dick Cheney’s bunker.”

For three hours, “The O’Franken Factor” mixed political barbs, comedy bits and callers ranging from former Vice President Al Gore to Watergate figure G. Gordon Liddy.

Bob Kerrey, the onetime Democratic senator from Nebraska who serves on the 9-11 commission, stopped by Air America, the new liberal radio network, which actually broadcasts from 41 floors above midtown Manhattan. So did populist documentary-maker Michael Moore.

A running gag had Franken checking in with “conservative bomb-thrower” Ann Coulter, purportedly locked in the show’s green room as the staff turned up the thermostat.

Conceived as a counterpoint to conservative talk radio, Air America debuted on six radio stations from New York to Los Angeles, and could be heard falteringly on the network’s Web site, airamericaradio.com, which struggled to meet demand. XM Satellite Radio also carries the 17 hours of daily programming — including shows with actress Janeane Garofalo and rapper Chuck D — on Channel 167, America Left.

Network IDs went along the lines of “Air America — farther to the left than the John Birch Society.” The network also claimed to outflank the National Rifle Assn. and Betty Crocker. Musical interludes included recordings from Grateful Dead concerts.

Advertisements spanned all tastes: Pitches for Jeep Grand Cherokees, the Army, a self-help book called “The Present” and the painkiller Advil ran on the quarter-hour. The show charges $1,500 per minute for ad time, compared with the $16,000 for Limbaugh’s show.

Franken said the new network “is about taking back our country. It’s about having fun. It’s about relentless hammering away at the Bush administration until they crack and crumble this November because, don’t get me wrong, friends, they are going down.”

He pledged to annoy O’Reilly, whose Fox News Channel unsuccessfully sued Franken for aping its “fair and balanced” slogan in the title of his latest book. “In the United States,” he said, “satire is protected speech, even if the object of the satire doesn’t get it.”

And he took a swipe at Limbaugh, whose midday show reaches about 20 million listeners on more than 600 stations, promising that Air America would be drug-free. Limbaugh has acknowledged abusing Oxycontin, a narcotic painkiller.

Not all listeners were amused.

One hundred minutes into the show, Bunsen, a Los Angeles blogger, yawned online: “I’m starting to contemplate the important metaphysical questions, such as ‘Could I possibly be more bored right now?’ Like, maybe if I found a can of paint and left it in that can in its liquid form and stared at the paint in the can while listening to a CD of whale songs, would I actually achieve a higher plane of boredom?”

Brian Schefke of Seattle wrote on the Pandagon blog: “I think it’s off to a good start. One caution I might throw out there is that while it’s good to use right-wing talk radio as a starting subject, I think that Air America shouldn’t define itself totally in opposition to it. In other words, it shouldn’t base its programming primarily on ripping … (Sean) Hannity, Limbaugh, etc., but should go off in its own direction.”