Mark Olwick, the Security Developer Center site manager, let me know about this eWeek article on the changes in WSE SP1. We're headlining the WSE download today on the Security Developer Center. Here's a link to the eWeek article:
Microsoft Add-On Secures Web Services
Microsoft Corp. has released an upgrade to its Web Services Enhancements technology for .Net developers.

The Redmond, Wash., company this week announced Web Services Enhancements 2.0 Service Pack 1 (WSE 2.0 SP1) for Microsoft .Net. The technology is an add-on to the company's Visual Studio .Net and the .Net Framework that enables developers to build secure Web services, the company said.