Our tipster doesn't have information on how those invites are going to be determined, other than the fact that it's Google doing the inviting -- if we had to guess, current registered developers are a strong possibility -- but the good news, we suppose, is that T-Mobile will apparently sell the phone directly at some to-be-determined point in the future.
ENGADGET: Exclusive: Nexus One full specs detailed, invite-only retail sales starting January 5th?