Well, maybe not at this particular moment. Thanks to a bout with food poisoning, the singer-songwriter is a day behind schedule, taking a commercial flight from his home in Nashville to play at the annual Taste of Chicago jamboree.

Not a great idea to entertain at a food festival when you've got a queasy stomach. But Barnes is thrilled to be opening for Bonnie Raitt, one of his musical idols and primary influences.

Finally this summer, after years of performing in any student center or small club that would have him, his music is being heard everywhere. Literally. Supermarkets, hardware chains, big-box mega-stores, you name it.

Last month, a company that programs music for retail outlets across the country added "Until You," the fetching romantic hit from Me & You & The World, Barnes' first label release, to its playlist.

Now Barnes, who is playing at the XPoNential Music Festival on the Camden side of the Delaware River on Sunday afternoon, gets about a dozen comments on his MySpace page a day with variations on this theme: "OMG! Heard you in Home Depot today. (smiley face)."

Yes, the world is finally catching on to Barnes' talent, which is gratifying because over three albums (two of them self-released) he has developed a surprisingly mature and engaging pop style that suggests a cross between Lifehouse and Bill Withers.

Spending nearly a decade trying to get attention makes him typical, he believes, in the iTunes era, when the once-mighty record labels are floundering and the music industry's star-making machinery gathers rust like the rides in some abandoned amusement park.

"For most of us who play music," Barnes says during a recent phone conversation, "this is blue-collar work. The glamour of five-second stardom - it's not like it was. The system that churned out that kind of success is broken for us. There's still American Idol and the people who get an iPod commercial and blow up. That still happens. But for most of us, you just keep playing shows and cranking."

Fortunately for Barnes, 30, he enjoys the endless string of one-night stands.

"There's no better thing than seeing the immediate effect of your music when you get on stage," he says. "Making CDs is terrific, but it can't rival the sensation of watching someone [in the crowd] when you start the first two bars of a song, say, 'Oh my God, I love this song!' That's a pretty huge motivator."

Barnes came to the joys of melody relatively late in life. When he enrolled in the music program at Middle Tennessee State in Murfreesboro, it was to major in drum.

"My roommate had just bought a guitar," he says. "When he wasn't home, I found myself playing constantly. I started listening to songs, how they were written, and I started writing songs.

"One of my best friends had an amazing voice," he continues. "I would play them and he would sing. We would demo them on a little tape recorder. After a while he said, 'I don't know if I need to keep singing these. I like the way your voice sounds.' That was so odd to me. I still thought of myself as a drummer.

"After a few times of him refusing, I would hole up in my room to record and stick pillows at the bottom of the door so no one could hear me singing," Barnes says. "After playing the tapes sheepishly for a few people, they responded positively. I can't describe just how shocking this was for me."

After graduating, Barnes moved to Nashville, where he was befriended by another aspiring singer-songwriter, Matt Wertz. The two would go on to write and tour together.

"Dave's songwriting work ethic is both inspiring and intimidating - oftentimes logging several new songs a week during 'writing season,' " says Wertz via e-mail. "His melodic instincts are prodigiously good. He's the guy you take a song that isn't 'quite right' to for his diagnosis and see what he prescribes. He's the melody doctor."

If so, he's a physician in the vein of Patch Adams, more slapstick than surgeon.

Anyone who has seen Barnes in concert knows he delivers the funniest between-song patter since Leo Kottke. Google his name and you'll find a wealth of YouTube videos in which he does voices, characters and comedy sketches. He's the perfect candidate to both host Saturday Night Live and be its musical guest.

"For me, that's what I've done the longest - skits and improv. Music came a little later," he says. "I pocketed the comedy for awhile because I didn't want to be known as a shtick guy. But a couple of years ago, I felt it had gotten to a place where people were into the music. I thought it was a good time to reintroduce the skits and do comedy shows. Now it's developed into it own thing."

He even does occasional straight stand-up shows in Nashville.

Listen carefully to Barnes' music and you can hear subtle religious references. Growing up in Kosciusko, Miss., (Oprah's hometown), the oldest of three children, Dave inherited a gentle strain of Christianity from his father, a Presbyterian pastor.

"There's two types of Christianity," he says. "One is with security lines and police tape everywhere and the other comes without fences. 'Here's the tools. Go live. You'll figure out where you fit in.' "

In his music and his life, Barnes wears his faith in his heart, not on his sleeve.

"I'll never write anything that contradicts what I believe in," he says, "but the faith that I have is a big thing and encompasses a great deal. It's not as limiting as a lot of people think."

With his popularity experiencing a dramatic growth spurt of late, Barnes might be tempted to pinch himself. But his wife, Annie, a pharmicist, handles that chore.

"My wife slaps my hand when I get cocky about how my music career is going," he says. "She's quick to remind me that I've never done anything to propel myself. It's been like the lazy river at Disney's Typhoon Lagoon."

Except your fingers don't get pruney.