GDSPlus allows you to specify what extensions the new Desktop Search tool from Google will index. This includes the ability to add new extensions not yet supported by Google, such as: .xml, .log (mIRC and Trillian), .cs, .vb (Visual Studio .NET source code files), .frm, .bas, .cls (Visual Basic 6 source code files), any other extension that can be indexed as text (not PDFs etc.).
Looks like a very useful, free tool for those who are using the Google Desktop Search.