Been using it since it was releaced and works great... Nice to install XAP's from IE... :)
Just a heads up for people trying...
Zune WILL relock your phone...
Open the Registry Editor on your phone. Now navigate to HKEY_LOCAL_MACHINE > Software > Microsoft > DeviceReg.
Now scroll to PortalUrlInt, remove its value data and save it. Do the same with PortalUrlProd. Both entries should now be "empty" (but not deleted!).