1: You should use 4wd on a limited basis. I've found that a drop in air pressure helps more than 4wd. I run 37-40 PSI normally, so I would drop to around 32-35 for snow driving. 4wd will put your front end components under stress, if you're turning and they aren't able to slip a little bit (like on wet or snow).
2: I *highly* recommend that you take your truck to a nice, big, open parking lot when it snows and HOON around. You will learn more about your truck playing around, drifting, testing traction control, etc. than any other driving condition. Be safe, of course, but it's fun and educational.