American Idol (8pm, Fox) - In the first part of a two-part season finale, Scotty McCreery and Lauren Alaina battle it out, singing three songs each. The winner will be announced in a two-hour finale airing tomorrow night at 8 p.m. There's an 'Idol' viewing party tonight at the Garner High School gym, and tomorrow night, the viewing party for the finale moves to the RBC Center in Raleigh. Both of those events begin at 7 p.m.
Biggest Loser Couples (8pm, NBC) - After viewer votes determine the third finalist, the winner of the $250,000 prize is crowned in the Season 11 finale. The eliminated players return to weigh in for the $100,000 at-home prize.
Frontline: Wikisecrets (9pm, UNC-TV) - Martin Smith examines the WikiLeaks scandal, in which classified U.S. material -- including secret cables and a controversial video -- was made public. Includes remarks from WikiLeaks founder Julian Assange and Brian Manning, the father of Army Pvt. Bradley E. Manning, who is accused of leaking the information.
Dancing with the Stars (9pm, ABC) - A winner is announced in the 12th-season finale.
Glee (9pm, Fox) - In the Season 2 finale, the glee kids head to New York to compete in Nationals and take in the sights and sounds of the city. Patti LuPone appears as herself.
The Voice (10pm, NBC) - Part 3 of the battle rounds continues. Reba McEntire, Monica, Sia Furler, and Adam Blackstone are the coaches' advisors.