Based on the strength of Iron Man's box office bow, Marvel Studios has thrown caution to the wind and decided to end a lot of fanboy speculation by revealing an ambitious line-up of titles...

2009:  Nope, nothing to be released this year.  First off, that's right around the corner so any major project would probably have been announced already.  Plus, there was that little thing called the Writers' Strike.

2010:  Iron Man's sequel will hit the screens during the same late spring slot as the current film, with an April 30 release.

Then, a little over a month later, on June 4, Thor will hit screens.  It will be directed by Matthew Vaughn, who helmed Layer Cake and Stardust.

2011:  The First Avenger: Captain America will arrive on May 6, followed in July by...

...The Avengers, which will feature all of the above characters, plus the Hulk.  Ubiquitous scribe Zak Penn has been tapped to write the script.   

source:  Variety