From Mediaweek:
Fox stood well above the Tuesday competition, with a two-hour edition of American Idol averaging a hefty 28.84 million viewers and an 11.2 rating/27 share among adults 18-49 from 8-10 p.m. Comparably, that outdelivered the four competing networks combined. As for the initial 12 male performers, Jason Yeager and Leif Garrett look-alike Garrett Haley would we wise to start packing. The best of the bunch (and the early favorites): teen David Archuleta and 29-year old Michael Johns.
For a rough comparison, Season 6 final numbers for the Top 12 Guys: 29.5 million viewers and an 11.8 rating/30 share among adults 18-49.