i would advise you to have an experienced lifter show u how to perform these, they are very complex movements and u can easily hurt yourself if youre not using the right form.... They have some olympic lifting books, check them out on amazon.com, im sure there are also some mpegs availible on the internet but i havent found any at the moment.
basically the snatch is a much wider grip and is finished in an overhead squat position with the weight locked out above the head, the arms do no bend throughout the movement.
in the clean the grip is much closer a little outside shoulder width, similar to conventional deadlifts, the weight is caught in a positon similar to the front squat with your elbows up, the arms are straight during the pull and then the elbows bend and the bar is caught above the clavicle, as your body squats under the bar
during both of these lifts you want to keep the bar as close to your body as possible and keep your back in a set positon, being careful not to round it off. I wish i had some videos online :-(, but i hope this helps to give a general idea of what the lifts are like