Alright Mac users, the Mac plug-in for silverlight is available for download from the Apple website:

http://www.apple.com/downloads/macosx/development_tools/silverlight.html

Mac System Requirements
  • Mac OS X 10.1 or later
  • 500MHz PowerPC G3 processor, 1.83GHz Intel processor, or higher
  • 128MB of RAM
  • Firefox 1.5.0.8, Firefox 2.0.x, and Apple Safari 2.0.4

Of course, the Microsoft Website also has links to download all of this for both Windows and Mac, plus the SDK and tools for development including Microsoft Visual Studio Codenamed "Orcas"...