By Steve Ryfle In four plus seasons of TV ratings domination, the mother of all talent contests has produced a handful of bona fide stars, a few dozen also-rans, and hundreds of wannabes. They've warbled through countless renditions of "My Girl," "I Heard It Through the Grapevine," and "I Will Always Love You." They've flinched at Simon Cowell's barbs, fawned at Paula Abdul's feel-good platitudes, and tried to make sense of Randy Jackson's dog pound woofs. But what happens to them after the last idol is left standing?

Success on "American Idol" means instant fame, even for contestants who become one of the 24 semifinalists and then fade out fast. Just how much post-show fame an "idol" enjoys seems to depend on a variety of factors - such as career choices, contract issues, and of course the fickle fans.

It seems like Kelly Clarkson has been a pop star in her own right for ages, but it's less than four years since she helped put Idol on the map by winning the crown in the show's debut season. During that time, she's essentially shed the cocoon that the show had wrapped her in, dropping the soft-pop sound of her debut solo album ("Thankful," 2003") for a more rock-edged sound on her second release ("Breakaway," 2004), which earned two Grammys. Along the way, Clarkson fired her first manager, "American Idol" creator Simon Fuller, completing her breakaway from the show that launched her career.

A lot of people (young girls, mostly) might argue that the real winner that first season should've been runner-up Justin Guarini. And for a while, it seemed Guarini was poised for stardom on equal footing with Clarkson, but his star has failed to rise. Due to legal constraints in his "Idol" contract, Guarini was prohibited from releasing his self-titled debut CD until nearly a year after the show ended - by which time, much of his career mojo had faded. What's worse, the CD was released around the same time as "From Justin to Kelly," a critically and commercially disastrous movie starring Guarini and Clarkson. Still, Guarini has soldiered on, acting in independent films and self-releasing a CD of jazz standards.

Since taking the season 2 title, Ruben Studdard has apparently settled into what will be a long, successful career as a respectable R&B and pop artist. His first CD ("Soulful," 2003) and his second, a gospel collection ("I Need An Angel," 2004) have sold well, but Studdard remains only the third-highest selling "Idol" alumnus. His success has been eclipsed by that of runner-up Clay Aiken, who's become something of a modern-day Barry Manilow, and who was voted "Favorite American Idol" by readers of People magazine in February 2006. With two highly successful CDs ("Measure of a Man," 2003 and "Merry Christmas With Love," 2004), high profile concert tours, a stint in Vegas, his rabid fans (known as "Claymates") and his good-natured acceptance of gay jokes about him, Aiken is a phenomenon.

In early 2005, season 2 contestant Corey Clark tried to attract attention to his fledgling solo career by claiming he'd had an affair with Abdul. It didn't work - nobody bought his CD, and a Fox investigation absolved Abdul of misconduct. Meanwhile, William Hung proved that even the worst singer in the world deserves his 15 minutes of fame, so long as he "tries his best," as the UC Berkeley student liked to say. Hung's awful rendition of "She Bangs" during the season 3 auditions was the stuff of legend, but now - after several CDs (including one titled "Hung For The Holidays"), an appearance on "Arrested Development," a documentary about him, and other overkill, it appears his 15 minutes have expired.

Season 3 winner Fantasia Barrino has been a dedicated workhorse since winning the "Idol" title. She released her debut CD ("Free Yourself," 2004), which emphasized her gospel-influenced sound, she made numerous TV appearances (including "The Simpsons" and multiple "Tonight Show" spots), and she opened for Kayne West on tour. But perhaps her biggest move was publicly admitting that she was functionally illiterate and taking steps to learn how to read and earn her high school equivalency.

Season 4 of "Idol" produced the biggest group of singers with name-brand potential, but it remains to be seen how long a shelf life each one will have. Winner Carrie Underwood's debut CD ("Some Hearts," 2005) was #1 on the country charts for 12 weeks, while runner-up and southern-rock holdover Bo Bice's first CD ("The Real Thing," 2005) peaked at #4 and is just the sixth-highest selling disc among "Idol" alums. Others who didn't make the final cut but were deemed to have big-money potential were Mario Vazquez, who quizzically quit the show after making it to the finals, and was rumored to have been in dispute with "Idol" producers over the show's highly restrictive contract (he has yet to release a CD); and cheeseball theatrical rocker Constantine Maroulis parlayed his "Idol" time into publicity for his band, and there have been reports of a sitcom deal and a solo CD.