See the Avid forum posting for more information about the release. The Avid web store will have the items at 12:30 Eastern Time.
As you're probably already aware, Liquid users wishing to upgrade will need their Liquid serial number verified to get the $1000 discount on purchasing MC 3.0. Resellers will handle verification. When I have more information about purchases from the Avid store, I'll report here. That will be no sooner than this evening. The store won't be updated before I have to leave for work.