The third season of ''American Idol'' doesn't start until January, but you'll be able to get an early glimpse of the talent pool next week. Fox announced that it'll show a sneak preview of the highlights (and lowlights) of the ''Idol'' tryouts, which begin this week in Los Angeles, during a brief segment on the Aug. 5 episode of ''American Juniors.'' During that episode, in which the six remaining ''Juniors'' finalists vie for the fifth and final spot in the ''Juniors'' vocal combo, ''Idol'' judge Simon Cowell will appear live via satellite to show viewers what Fox says is ''the good, the bad and the outright awful'' from the L.A. tryouts. Actually, Simon won't be broadcasting from Los Angeles; he'll be home in London. Guess some of the ''Idol'' hopefuls are so hopeless that he didn't want to be within 6,000 miles of them.