I had several people asking me for some details about what exactly is fixed in 3.0 SP1 - so here is some more information.
The .NET Framework 3.0 Service Pack 1 fixes the problems that are described in
the following articles in the Microsoft Knowledge Base:
932471 FIX: Error message
when you try to open or to create a protected XPS document by using the XPS
viewer that is included with the .NET Framework 3.0: "Cannot open this document
because your permissions have expired" 932816 FIX: You experience
various problems in Windows Workflow Foundation 935314 FIX: You may
experience issues with Windows Communication Foundation peer channel connections
935315 FIX: The COM+
application cannot start when you use the COM+ Service Model Configuration tool
to expose the COM+ components in the COM+ application 935434 FIX: Error message
in FIPS-compliant systems when you use Windows Communication Foundation to
serialize generic types: "This implementation is not part of the Windows
Platform FIPS validated cryptographic algorithms" 936123 FIX: Error message
when you open a workflow by using the workflow designer in Visual Studio 2005:
"Error loading workflow" 936512 FIX: A memory leak
occurs when you send many messages by using the NetMsmq transport in the .NET
Framework 3.0 938758 FIX: The Unload
method may stop responding (hang) in a Windows Workflow Foundation project
942520 FIX: You may
experience slow performance when you run a Windows Communication Foundation
application