Today we posted new content around .NET Framework version compatibility. Here's a link to the primary document:
Microsoft .NET Framework 1.1 and 2.0 (Beta) Compatibility
The Microsoft .NET Framework 2.0 builds on the success of the Microsoft .NET Framework 1.0 and 1.1 to provide the best runtime environment for Web and Microsoft Windows client applications. Microsoft's compatibility goal for .NET Framework 1.1 applications is that they should work smoothly on the .NET Framework 2.0 except for a set of documented changes. During the Beta 2 release, we have not yet achieved this goal and are seeking feedback on application issues that can be addressed before the release of the .NET Framework 2.0. This document discusses application compatibility scenarios and provides recommendations on best practices for different segments.
The other documents include Compatibility Testing Scenarios and the List of Breaking Changes.