Moonlight 1.0 Beta 1 (Download) runs well in Firefox 3 on Fedora 10 x86_64, but many websites uses Silverlight 2.0. The roadmap of Moonlight says the 2.0 alpha release will be on 3/18/2009.

I picked up one site to test video and audio from test sites list1. Moonlight prompted for installing Microsoft Media Pack, after installed, refreshed the page and it played. The INSTALL2 has more information about what Moonlight uses to play.

If you want to test 2.0, then you will have to compile on your own. It’s at pre-alpha stage, probably not a good idea to do unless you are very interested in Silverlight. Besides, Flash still rules the world, I barely see websites use Silverlight. (I don’t go to microsoft.com)

[1]http://go-mono.com/moonlight/MoonlightStatus.aspx is gone.
[2]http://anonsvn.mono-project.com/viewvc/tags/moon/1.0b1/INSTALL?view=markup is gone.