WSE 3.0 was released last year, and here is the download link:
http://www.microsoft.com/downloads/details.aspx?familyid=018a09fd-3a74-43c5-8ec1-8d789091255d&displaylang=en
It is built on top on .NET Framework 2.0 and it is a very exciting release!
For more insights of security in WSE 3.0, check out my recorded sessions at