I often receive emails asking about the documentation for Xen and wanting to see an upgrade, etc. The latest documentation that I am aware of is at this page: http://xen.org/xen/documentation.html
The Xen 3.0 documentation is out of date, as I often get told, and I am looking to see if anyone in the community is interested in updating the documents; especially with the new release coming out this month. If you are interested in working on the documentation please send me an email so I can post and track what you are working on. This way we avoid duplication of effort.