My husband got me interested but couldn't teach me well. I found a women's group and learned a ton from them. A lot of us the got into mountain biking because of a boyfriend/husband have found the see, feel and communicate the sport differently and riding with women was our biggest confidence booster.
Climbs, it depends on what is happening. My climbing position is as far up on the nose of the saddle like Irulan described. One of the women I took classes with called it "very intimate". It isn't exactly comfortable. The other thing I learned is "boobs to the tube". It sounds funny so you remember it. Basically is bending at the waist, rolling your hips so your chest is lowered towards the top tube. This changes the center of gravity to give you a firmer feel under you. These work for rooty, loose uphills for me. Still working on ledges.
Finally crashing is part of mountain biking especially when you are new. Some women I ride with find knee pads and elbow pads give them a little extra comfort if they might crash. Good luck, my learning curve was steep but I love mountain biking and I came from a long distance road riding background but the dirty side is my passion now.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan