The Latino Review is reporting that the role of Howard Stark, founder of Stark Industries and father of Tony (a.k.a. Iron Man), may be taken over by Shawshank actor Tim Robbins.
If this casting rumor is true, director Jon Favreau's decision to dump Gerard Sanders, who appeared in the part for the first movie, will be because of an enhanced role and important story arc which may introduce The Avengers and Captain America in particular.
This means that the elder Stark (and Robbins) will play a big part in Marvel's multiple comic book movies, and will probably involve Stark's company in the WWII Super Soldier experiment that created Captain America. Such set-up in Iron Man 2 will most certainly follow through in the two other Marvel movies -- already in pre-production.
Also mentioned as possible players in Iron Man 2 are two other Avengers: Black Widow and
Hawkeye.