Read THE Silverlight blog post
If by chance you're the *one* person who reads my blog yet does not read ScottGu's blog, you definitely missed the best post on Silverlight to date. While many folks have talked/blogged about Silverlight, Scott's post includes all the information you could want in a single place. I definitely recommend the keynote/videos if you haven't seen them.
I previously blogged that the new Silverlight community site is running Community Server 2007 but I'm also happy to mention that they're leveraging Morpheus to share membership with the www.asp.net suite of sites. So if you've previously registered at forums.asp.net you should be able to simply login to www.silverlight.net and you'll be able to post to the forums. There are currently about five sites all leveraging the same membership store and more to come online soon. It's nice to see Morpheus working for these large (read: heavily visited) Microsoft sites.