ITC Fusion is a wiki that focuses on teaching life skills while teaching the state mandated curriculum. It has some nice Boardmaker boards and other resources.
ATEN Region 3 Village is a wiki about creating thematic visuals and accessible literacy activities.
Ohio Alternative Assessment has great information for all of working to do alt assessment or teach to state or local standards.
I am also beginning to work on an intensive special needs wiki, but it will most likely be a summer project. It is located at Intensive SPED Resources if you want to check my progress.