Walt Disney Pictures has set the release date for Iron Man 3 for May 3, 2013.  This news from Exhibitor Relations' Facebook page comes on the heels of a press release from Disney announcing that they had purchased the distribution rights for Iron Man 3 and The Avengers from Paramount.  It's worth noting that if this release date holds, Iron Man 3 would come out almost one year after The Avengers, which is slated for May 4, 2012.

Nothing is set in stone at the moment, but presumably all the actors who signed on for Iron Man 2, signed multi-picture deals so Marvel and Disney can choose who they want to bring back.  The biggest question mark is whether or not Jon Favreau will helm the third film.  As you may recall, there was some protracted negotiations between the director and Marvel over coming back for the sequel.  However, Favreau has already said that if he returns, he would like The Mandarin to be Iron Man 3's villain.