A quick push out the door before the UC.

ArcGIS (Desktop, Engine, Server) 9.3.1 Service Pack 2

ArcSDE 9.3.1 Service Pack 2

ArcIMS 9.3.1 Service Pack 2

ArcGIS Image Server 9.3.1 Service Pack 2

You can also see a list of the issues addressed with this Service Pack.