American Idol Season 9 Episode 43 (American Idol s09e43) with title “Winner Announced” airs on Wednesday, May 26th 2010 at 08:00 pm via FOX.
Here is summary for :

The winning singer is named in the conclusion of the Season 9 finale. Included: a reunion of the Top 12 contestants

Few hours after original series aired on TV, online streaming video for American Idol Season 9 Episode 43 usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.