I ran into a problem with the download, Eagle, and many developers may, but there's an easy enough path to alleviate it.
Your Silverlight developer components are out of date.
If you have a dev. env. on your box and don't already have the Silverlight 3 tools installed, you will want to hit the link below first before installing Silverlight 3...
http://go2.microsoft.com/fwlink/?LinkID=119972
then
Download Now
EDIT: AACCKK! the link I put up above, which the Silverlight 3 install yields upon the error, is for Silverlight 2 dev. tools which I already have installed! Time to hunt them down...
Who should be notified of this obvious oversight?
This is the offending page: http://www.microsoft.com/silverlight/resources/help.aspx?errorID=1512
I just filed an incident report with support.microsoft.com 