Do you have the vocal chops of a Kelly Clarkson, the fashion sense of a Clay Aiken, the stage moves of a Ruben Studdard, or simply the unshakable self-confidence of a Frenchie Davis? Then you probably already know that tryouts for the third edition of ''American Idol'' start in just three weeks. ''Idol'' producers have announced that open auditions begin in Los Angeles the first week of August (either Aug. 4 or 6; the producers haven't decided yet), then in Houston on Aug. 13, Atlanta on Aug. 20, and New York on Aug. 25. (Tryout locations in those cities will be announced later, and the dates are subject to change). The show's tireless judges will winnow down the likely tens of thousands of applicants to the handful who will compete for the $1 million record contract when the show's third season begins in January. Just remember, ''Idol'' hopefuls, if Simon Cowell heckles you, you can always razz him about the low ratings of his CBS dating show ''Cupid.''