I know it's kinda early to be talking about this but there has been a good bit of speculation about where the Mustang's 45th anniversary show would be held. According to the MCA website it's going to be at the Barber Motorsports Park in Birmingham, Alabama. The dates are confirmed for April 17th, 18th and 19th of 2009.
The Mustang Club of America commemorated its 30th anniversary there in September of 2006 and, as venues for a car show go, it's a pretty good one. There's a road course that looks more like a golf course with a racetrack running through it and a large paddock area where show cars can be parked and wandered-among.
There are plans in the works for several groups of Mustangs to caravan to the celebration from several different directions so you should be able to find one that is going the same direction you are and join in.
Details about the event will be available as they are finalized at the MCA website:
Mustang Club of America
So, who's planning to go? It should be as much fun as the 40th was in Nashville but without the dust from the gravel show field.