Marvel has got a lot of comic book film adaptations coming out, but they've just recently had to making changes and adjust their timeline for when certain movies will be coming out (barring future problems that could always happen). The new projected timeline is as follows:

Iron Man 2
May 7, 2010 - May 7, 2010

Thor
July 16, 2010 - June 17, 2011

The First Avenger: Captain America
May 6, 2011 - July 22, 2011

The Avengers
July 15, 2011 - May 4, 2012