I follow Nascar as close as I follow F1.
This is what I think.
Chip Ganassi like Dave guesses will be in a Toyota in 2008 as will penske
Both of their contracts are up at the end of 2007 with dodge.
JPM got a guaranteed contract for two years. I am guessing he will use the first year to learn. Chip ganassi while he is cheap will spend a ton of money next year. Montoya is a God send to him as the American media and people love JPM and this will introduce Nascar to the Latin community here as JPM will be able to speak spanish. I also heard from a good source that Nascar is paying most of if not all his salary for the next year and its much more than he was making in F1. Keep in mind that in the states Nascar is second in sports only to american football. Lets not forget also that with Chip Ganassi he could run the indy 500 again and win it again.
For JPM to have went to CART or the IRL with the way the series is today would have been a huge step backwards. Like Villenuve said, NASCAR is not a step down from F1. Its differant, but not a step down.
Chip Ganassi has not won a nascar race for a few years. If JPM could pull it off it would cement his name among some of the greats. Its too bad a F1 title will not happen, but a Nascar title to go with his CART title ( when cart was credible) along with wins at Monaco and the Indy 500 looks pretty dang good.
As far as F1 goes, the only two teams that can win a title is Ferrari and Renault. Unless your in one of those two cars, you can maybe pull of a win, but no title. The Mclaren was clearly built around Kimi as is the renault for Fernando and the Ferrari for Michael.
JPM has beaten his team mates everyplace he has been. At Mclaren he never had a chance.