Hey Mitch, as you noticed you can still use a good amount of the XML support as far as the reference schemas go. You can work with the Word and Excel schemas as well as some of the XSLT support.
The customer defined schema support though isn't in every SKU, and there is really a ton of power there.
If you're looking to try out some of the functionality, there are some online labs available (as I pointed out
You can also get a trial CD of Office 2003 Pro