I'm happy to say IE8 Security Program Manager and Fiddler author Eric Lawrence announced our Watcher tool at MIX09 today. Check out his talk at http://videos.visitmix.com/MIX09/T54F it's an eye opener for Web developers – introducing us to the new features of IE8 while also covering state-of-the-art secure development practices for today's Web applications.
Unfortunately CodePlex went down today, even with Microsoft's new release of !exploitable at CanSecWest. Anyhow we're working hard to to add new checks to Watcher and reduce false positives in existing ones. So please grab Watcher from Codeplex and send us any feedback you want.