Url: http://www.microsoft.com/downloads/details.aspx…

There is an updated build of Expression Blend’s August Preview.  For some users it complains that wants a CD key and has an expiration date soon (mine is at seven days).  It was supposed to work without a CD key and it looks like they’ve fixed it.  Tim Heuer mentioned the new build so if you’re having the problem, please download this new version