This could be just a little reminder on Silverlight 3 (you know MIX 09 yadda, yadda, yadda) but perhaps it can be a little bit more for you.
Check out any download in Microsofts Download Center for Silverlight 2 and you will see something like the following on the “Thank You” page which appears after the download itself.
Clicking on this link brings you to a “coming soon” page. Might this be true for everybody? Perhaps you can just adjust you user-agent string to get access? I don’t know. If you have access to MS’ intranet, it looks like you can download SL3 Tools from here (found via this one).
Sorry, just a litte teaser 
And look out for LOB functionality in SL3.
Best regards,
- tobias