I grew up riding rocks in New England before moving to the midwest about 6 years ago. I can tell you one thing, I DON'T MISS THE ROCKS!!!
Anyhow, going uphill on rocks, speed and momentum are key. I try to stay in a taller gear to lessen wheelspin. If you can keep your speed, the suspension should help suck up the rocks. Once you slow down, the suspension won't work as well and it will kill your momentum and then you're cooked. Standing up is way better riding rocks and a steering damper helps BIG.
As for decending, the back brake is still essential. You just need to be able to modulate it without locking it up too much. I sit down, lean back, and work the front AND rear brakes lightly. Obviously, once you lock up either, the decent gets much more interesting :)
The great thing about riding in New England...once you can ride rocks well, chances are you can ride well anywhere in the country.