It would be cool if this edit could make these "cannon" as well:
A few perceptive observers noticed during the theatrical run of "Iron Man" that in the scene where Pepper Potts (Gwyneth Paltrow) walks in on Tony Stark (Robert Downey Jr.) as his armor is being removed, there was something on the workbench behind him. Circular, with red and white stripes and a half-completed star in the center, it was speculated that this was Captain America's iconic shield. 
In a Q&A session in Santa Monica last month, director Jon Favreau confirmed that it is indeed Cap's shield. He said a visual effects artist at Industrial Light & Magic 
had placed it there just as a joke. But Favreau loved the little "Easter egg" and decided it should stay.
Captain America himself made a cameo in "The Incredible Hulk," but don't feel bad if you didn't see it. While director Louis Letterier had hinted in interviews that they had shot an appearance, the scene ended up on the cutting room floor. But now it can finally be seen in the bonus features on the DVD, as first spotted by FilmSchoolRejects.com.
In the original opening scene of the movie, Bruce Banner (Edward Norton) travels to the Arctic, away from civilization, to try to end his own life and rid the world of the Hulk. 
There, buried in the ice, is the frozen body of Captain America. It's a little difficult to make out the figure, but again he can be identified by his shield.
The character is scheduled to get his own film, called "The First Avenger: Captain America," in May of 2011. Then he's expected to join Iron Man, Hulk, Thor and other Marvel heroes in the group "Avengers" movie that July. The speculation is that the first movie will be his origin story, set during World War II like the initial comics. Then he will be frozen and brought back in modern times to join the team, just like he did in the books. Jon Favreau has stated he'd like to direct "The Avengers," but first he's focusing on "Iron Man 2," hitting screens in May 2010.
from http://movies.yahoo.com/feature/captainamerica_blog.html
Didn't Tony also use the shield to fix something in Iron Man 2?