Fox cruised to victory on Wednesday night behind “American Idol” and the premiere of the latest round of “The Simple Life,” according to preliminary nationals from Nielsen.

As it completed its second week, Wednesday’s hourlong auditions episode of “American Idol” (11.2 rating/28 share in adults 18-49, 26.5 million viewers overall) again dominated its 8 o’clock timeslot, beating the broadcast competish combined in key demos. And from 9 to 10, the premiere of “Simple Life 3: The Interns” (6.2/14 in adults 18-49, 13.4 million viewers overall) delivered the franchise’s second-best demo average and its largest overall audience, winning across the board.

CBS was led by an original episode of “CSI: NY” (5.8/15 in adults 18-49, 17.3 million viewers overall), which won at 10 over NBC’s Katie Couric news spec “The 411 on Teens and Sex” (3.6/9 in adults 18-49, 9.2 million viewers overall) and a repeat of ABC’s “Wife Swap” (3.0/8 in adults 18-49, 7.0 million viewers overall). The Eye also was solid from 9 to 10 with an original and repeat of “King of Queens,” which averaged a 4.1/9 in adults 18-49, 11.5 million viewers overall.

ABC was paced by “Alias” at 9 (4.9/11 in adults 18-49, 11.8 million viewers overall), which ran second to “Simple Life” and built on its repeat “Lost” lead-in (3.9/10 in adults 18-49, 12.0 million viewers overall).

NBC again struggled at 8 with “Sports Illustrated Swimsuit Model Search” (fifth-place 1.6/4 in adults 18-49, 4.3 million viewers overall), making it tough at 9 for “West Wing” (fourth-place 3.2/7 in adults 18-49, 10.7 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 8.7/21; CBS, 4.0/10; ABC, 3.9/10; NBC, 2.8/7; WB, 1.4/3; UPN, 0.9/2.

In total viewers: Fox, 19.9 million; CBS, 12.7 million; ABC, 10.3 million; NBC, 8.0 million; WB, 3.0 million; UPN, 2.4 million.