Martin Normark has written an excellent guide on how to debug a Silverlight application running on OSX through a local Visual Studio 2008 session on Windows.
The ability to not only run cross-platform, cross-browser but also to debug cross-platform is one of the really amazing things about Silverlight.
Check it out here!
And be sure to check out all the latest editions to the Silverlight Showcase. There are well over 100 applications now in numerous searchable categories. I was surprised how many new ones have been added over the holidays, be sure to check it out.