According to someone at the source, "the unit patches reveal that he's part of the 29th Infantry division, which landed at Omaha Beach on June 6th."
Also, it's been confirmed that Captain America will make an appearance in Hulk, like his shield was seen in Iron Man. (I hope it's something obscure like him being seen in a block of ice, or something.)
Maybe Cap will make an appearance in Wolverine, too? :D