According to Moviehole.com Sam Raimi wants to turn his attention to a sequel of Army of Darkness. One can only assume that Bruce Campbell would have to be in it (fans of the Evil Dead series, rejoice!).
Many thought that any shot at a fourth "Dead" movie was, well, dead following the recent announcement that a remake of the original Evil Dead movie had been approved by Raimi. The remake will not be directed by Raimi and will not star Campbell. Fans of the original movies were not happy and questioned the point of a remake.
It will certainly be a while, and thinks could change since Raimi is interested in doing this after Spiderman 3, but we can keep our fingers crossed, baby. :P