We just got the confirmation from Samsung Galaxy S support account on Twitter that Android 2.2 update for Samsung Vibrant is finally out.
It is over the air update, not from Samsung Kies, so wait for the notification on your Vibrant, you will soon see it, then just hit download.
Share you experience with Android 2.2 on Vibrant in the comments.
UPDATE: It seems the update is not Android 2.2, it is just a regular performance update with GPS fix. We apologize for the mis-information earlier.