I'm now using MSBuild and WiX for all of my active projects. I ended up with a few VS2003 solutions that I didn't want to convert to VS2005/MSBuild format for one reason or another. It is a pain keeping Windows Forms applications compatable with .NET 1.x when editing using VS2005. I also wanted to be able to compile NUnit for .NET 1.0 using the VS2003 solution strait out of SourceForge.
I kept meaning to post about compiling for .NET 1.x using MSBuild. I had everything working on my machine, but getting everything into the right place was a little involved. I've ended up writing an installer that collects together all the files you need along with the required modifications.
You can find the installer and documentation here.
Using it is very straightforward. Say you wanted to compile a VS2003 (or VS2005/MSBuild) solution for .NET 1.0. After installing MutantBuild, execute the following from the command line...
> mutantbuild @debug(1.0).response your.sln