NET Framework 2.0 (CodeName: Whidbey) is the buzz word around and most of us would have installed the BETA versions to try our hands.
However, after you install .NET Framework 2.0, if you continue to use Visual Studio.NET 2003 you may be unable to debug the applications developed in .NET 1.1. You may receive the error "Unable to start debugging on the webserver..."
This Article explains the scenario and provides the solution for the same.
Hope it helps.