(Reuters) - Finalist David Cook (C) sings 'Sharped Dressed Man' with ZZ Top during the finale of 'American Idol' at the Nokia Theatre in Los Angeles May 21, 2008. Cook won the American Idol competition. (Mario Anzuoni/Reuters)

(Reuters) - Ruben Studdard (R), 2003 American Idol winner, and unidentified date pose on the red carpet at the finale of the American Idol television show in Los Angeles, California May 21, 2008. (Fred Prouser/Reuters)

(Reuters) - Bryan Adams performs a medley during the finale of 'American Idol' at the Nokia Theatre in Los Angeles May 21, 2008. (Mario Anzuoni/Reuters)

(AP) - American Idol winner David Cook stars in Activision's new Guitar Hero commercial. (Photo: Business Wire)

(AP) - American Idol runner-up David Archuleta stars in Activision's Guitar Hero commercial. (Photo: Business Wire)

(Reuters) - Singer Seal (L) performs 'Waiting for You' with Syesha Mercado during the finale of 'American Idol' at the Nokia Theatre in Los Angeles May 21, 2008. (Mario Anzuoni/Reuters)

(Reuters) - Performer Renaldo Lapuz sings during the finale of 'American Idol' at the Nokia Theatre in Los Angeles May 21, 2008. (Mario Anzuoni/Reuters)

(Reuters) - Donna Summer performs during the finale of 'American Idol' at the Nokia Theatre in Los Angeles May 21, 2008. (Mario Anzuoni/Reuters)

(Reuters) - Paula Abdul, one of the judges on the American Idol television show, has her gown tended to by a publicist as she arrives for the show's season finale in Los Angeles, California May 21, 2008. (Fred Prouser/Reuters)

(Reuters) - Finalists David Archuleta (R) and David Cook face off during the finale of 'American Idol' at the Nokia Theatre in Los Angeles, May 21, 2008. (Mario Anzuoni/Reuters)