Most stylesheets I've seen so far are using XSLT 1.0 specific stuff. Especially because Mozilla requires it. It's been mentioned before that it's highly recommended to upgrade the MSXML parser. There are links in other threads to good info about it.

The working draft spec is pretty limited. It doesn't support a lot of the XPATH functions that people are using (like position()).

You might also want to check the netcrucible msxml faq