Update: Since the release of this post XenDesktop 7 has been released and most information can now be found in Citrix eDocs.
Citrix XenDesktop 7 has been announced during the Citrix Synergy keynote in May.
XenDesktop 7 will be available before the end of June.
The following resources on XenDesktop 7 are currently available:
XenDesktop 7 Features and Entitlements (My Citrix logon required)
Master Class XenDesktop 7 webinar (June 19)