Some great stuff going on with XML lately. 

• Jan Tielens shows how to use InfoPath to access a secondary datasource, such as a SharePoint list
• Matt Warren then delves into some XML bestiary and shows a binary XML parser based on XmlReader. 
• Cazz (the one and only avid bathreader) shows how to iterate over XPathNodeIterator nodes, provided that you know the underlying type that is being iterated over.
• WSE 2.0 is code complete.  I am really late to the game posting this, but it is great news.

I really hope I get some time to finish and post up the 2 code tidbits I have been working on to further the XML bestiary.