WWE SmackDown is now listed on iTunes. So far the only episodes available are from the last two weeks: 3/18/11 and 3/25/11. The March 18th episode is free and the March 25th one is $2.99.

Also on iTunes is The Rock's update theme called "Electrifying" for $1.29.

Below are lists of all the PPV's and documentaries you can find on iTunes.

The following are listed under "TV Seasons":

WWE Elimination Chamber 2011
WWE Survivor Series 2010
WWE TLC 2010
WWE Bragging Rights 2010
WWE Over the Limit 2010
WWE Fatal 4 Way 2010
WWE SummerSlam 2010
WWE Money in the Bank 2010

The following are listed under "Movies":

WWE: The Top 50 Superstars of All Time
Legendary
The Rise & Fall of WCW
Twist of Fate: The Matt & Jeff Hardy Story
Breaking the Code: Behind the Walls of Chris Jericho
Hart & Soul: The Hart Family Anthology
Bobby "The Brain" Heenan
Ricky Steamboat: The Life Story of the Dragon

Source: wrestlinginc.com