Yes, this is legitimate and officially sanctioned. Microsoft is releasing the beta version of Vista Ultimate for download. This page gives details on the download. It is also possible to request a dvd. (The download is a dvd iso – a bit over 3 GB). It will expire June 1, 2007 (I assume Vista will be out by then…) It should be able to upgrade an existing XP install or do a fresh install (PLEASE DO NOT DO THIS WITH YOUR MAIN DESKTOP WITHOUT SERIOUS BACKUP FIRST.) It will be unable to roll back to the previous OS (fresh wipe and install would be required.)