Rcmt is a great site for radio control monster truck info. There is an incredible amount of info here along with a great group of people to help you out if you need it.
Clodtalk is a site geared towards the clodbuster by Tamiya. But you will find more info than just clod info.
The NRCTPA is club that I run with. They are dedicated to running radio control truck and tractor pulling along with radio control monster truck racing.