As you may know, Fedora 16 will have full Xen support for Dom0 and DomU in it. Fedora is planning a number of test days as part of their release cycle, including a Virtualization Test on September 15th this year, which is tomorrow.
We are calling our community members to participate in the test day tomorrow: certainly many of us here at the Xen Hackathon in Munich are planning to do so. As always every extra volunteer who wants to help is very welcome.
Information about the virtualization test day can be found here. We will have some people hanging out on IRC at #fedora-test-day and you can also get in touch with us via the usual channels.