From the Miguel dept.:
Today we are making the first public release of Moonlight, supporting the Silverlight 1.0 profile for Linux. The release comes in two forms:

* No-media codecs supported, but easy to install: head to http://www.go-mono.com/moonlight and click on the cute installer for Moonlight. This currently hosts builds for Linux x86 and x86-64 for Firefox.
* Source-code compilation, but you can optionally compile FFMpeg codecs yourself. To do this, download our moon-0.6.tar.bz2. And follow the build instructions.

Although Moonlight works on Firefox 2 and Firefox 3, recent changes in Firefox 3 prevent Silverlight and Moonlight from working (For details see #432371, #430965). There is a user contributed Greasemonkey script that will work around this bug for some sites (requires Greasemonkey).

Miguel