For alternative and indie bands, television has suddenly become the new radio -- a crucial outlet for music ignored by increasingly homogenized commercial radio stations and video channels.

The leader in this brave new world is Fox's "The O.C.," which premiered in August 2003 and kicks off its second season on Thursday. Reaching the desperately desired 12-to-24 demographic, "The O.C." and others -- think "Gilmore Girls," "Joan of Arcadia," "Smallville," "Everwood" and the new "life as we know it" -- offer bands mainstream exposure and a way around tight playlists.

"The O.C." is a prime-time soap opera about ever-shifting romantic relationships, familial entanglements, class conflicts and the awkward coming of age of its three teenage protagonists: Seth Cohen (Adam Brody), Marissa Cooper (Mischa Barton) and the inevitable outsider, Ryan Atwood (Benjamin McKenzie).

In providing a credible soundtrack for their lives -- and cannily underscoring plot, dialogue and character development -- "The O.C." has become the show to turn to for great tunes you won't hear on the radio. Out of Marissa's and Seth's mouths also come the names of underground bands probably unfamiliar to most viewers, including Death Cab for Cutie, Modest Mouse, Rooney and Phantom Planet, whose insistently catchy "California (Here We Come)" serves as the show's theme song. All have seen significant spikes in airplay and sales and, in some cases, increased attention from major labels.

No wonder musicians are jockeying for spots on "The O.C." soundtrack and its commercial progeny. "Music from The O.C.: Mix 1" came out in March, and two more "Mix" albums were released recently.

"Music From

The O.C.: Mix 3: Have a Very Merry Chrismukkah" -- songs by Rooney, Ben Kweller, the Raveonettes and Jimmy Eat World -- will feature music from last year's bi-religious episode, "The Best Chrismukkah Ever," and from this season's holiday episode scheduled for Dec. 16.

And this season, "The O.C." will have a lot more live music, thanks to the newly opened Bait Shop, an all-ages club where the characters will hang out. Performances by the Walkmen, Modest Mouse, the Killers and the Thrills already have been filmed.

The youth-and-music angle shouldn't be too surprising: At 26, creator and executive producer Josh Schwartz became the youngest person in network history to create and run the day-to-day production of a network series.

"I always knew that the music was going to be used to illuminate the emotional lives of the characters," Schwartz said. "It wasn't 'music from O.C.' or music that was cool on the radio, because it wasn't [on the radio]. It spoke to me and it spoke to

the characters about what

they were going through and feeling."

Schwartz, who said he is often unable to write a scene until he finds the right song to accompany it, tries to get "as many songs as I can into the script. It's inspiring, sustaining."

For the first seven episodes, the music came directly from Schwartz's iPod, reflecting his interest in acts such as Joseph Arthur, Doves, Jeff Buckley and Turin Breaks. That's when music supervisor Alexandra Patsavas signed on; she now sends Schwartz and the show's producers a weekly 20-song compilation CD with material she thinks is appropriate to the show.

Or, she said, "they might call me and say 'I really need a breakup song' or 'I need a song for this specific moment,' and I often find myself pitching for specific scenes as they come up in the editorial process. Sometimes there's clearly a winner, clearly the perfect song, and sometimes it takes a long time and many, many choices to find the perfect song."

While at the University of Illinois -- Urbana in the late '80s, Patsavas booked university venues and local clubs, what she called " 'The O.C.' bands of the day, alt-rock bands like Nirvana, Afghan Whigs and Soul Asylum. I feel like the times in music now are really rich just like they were then -- except that radio doesn't realize that music is so good again."

For research, Patsavas has multiple resources: Her Sunset Strip office is across the street from Amoeba Records, the country's largest indie store.

"I listen to satellite radio and go to shows," she said, often with "The O.C.'s" music-savvy young actors, who also provide essential feedback. "And since I've been doing this for a while, I have friends in management so I hear a lot of brand-new things, even demos."

Since "The O.C.'s" out-of-the-box success, Patsavas has been inundated with material, both commercially released and from unsigned bands.

"I just listen and hope for good songs, but, honestly, the songs have to fit the show. We first have to serve the picture, serve the characters and the emotions of the characters."

Now she's eager to kick-start the new season, which started shooting July 7.

"We have five months of great songs that we can't wait to get on the air," Patsavas said. Some stellar big names are also in the mix: a new U2 song, "Sometimes You Can't Make It On Your Own," shows up in Episode 4, and Episode 5 features "Cool," a track from Gwen Stefani's upcoming solo debut -- made cooler, Patsavas pointed out, by the fact that "she's an 'O.C.' girl, absolutely."

Patsavas's Faves

Alexandra Patsavas finds tracks for several shows including "Without a Trace," "Carnivale" and "The Mountain." Three of her favorite songs from "The O.C.":

n Finley Quaye, William Orbit and Beth Orton's trip-hop ballad "Dice," used at the end of the New Year's episode "The Countdown." "A great musical moment," Patsavas said.

* Nada Surf's cover of OMD's 1986 hit, "If You Leave" in "The Goodbye Girl" episode, when Seth is saying goodbye to girlfriend Anna at the airport. "We specifically commissioned them to cover it. That was my youth and Josh's youth and a great old song that I felt became really relevant again."

* A double of Franz Ferdinand's "Jacqueline" and the Beastie Boys' "Ch-Check It Out," both used in the Las Vegas-set "The Strip" episode. In a bow to the show's power, the Beastie Boys approached "The O.C." with their comeback single after a six-year break. "That was incredibly flattering," Patsavas said. "They're so difficult to license and have not been much involved in TV at all, so I was thrilled."