Looks like a few teams have already committed to running the Toyotas. As expected, Bill Davis Racing (22 CAT car, 55 Napa car) are among the teams listed. They helped bring the Toyota into the truck series. Michael Waltrip who will drive at Bill Davis racing in 06, will break off and field a two car team in 07, and a new team owned by Red bull

will field two cars. So that's 6 cars confirmed for 07.
I think it's quite intersting that Red Bull will field a NASCAR team, they've moved into every other motorsport on earth, I supposes this is a natural move for them.
http://msn.foxsports.com/nascar/story/5277006