Until you can get some coaching (actually even with the coaching), I highly recommend Nedly's video.

http://www.amazon.com/exec/obidos/tg...video&n=507846

It really helps explain body positioning for basic maneuevers and various techiniques that will help in the learning process. As roadies, we tend to sit in one spot and pedal. For example, a roadie almost always pushes her butt back on the seat to climb. On the dirt, you may need to put the tip of the saddle "where the sun don't shine" to get up a steep hill. It's the opposite of the habits you've built up over your thousands and thousands of road miles.