BooLangStudio is a CodePlex project to provide Visual Studio integration for the Boo language.  Torkel Ödegaard wrote  this post about the recent progress. 

Intellisense support has been improved and debugging works.  Good stuff!

Currently SharpDevelop is still the better option for boo coding, but BooLangStudio deserves some love and support because if Boo works in Visual Studio, it will reach a much larger audience.