questions about shoulder pressing

for my weight lifting class, i have to do a report on free wight shoulder press. i was wondering if anyone could tell me the muscles that are worked in shoulder pressing, what the correct form is: (A. starting position, hand/foot position, grip, etc.), (B. descen;: flexation), and (C. ascent; extension). and does anyone know where i can find a picture of a person doing this exercise on the internet? thankyou for you time

db:
http://www.exrx.net/WeightExercises/DeltoidAnterior/DBShoulderPress.html

bb:
http://www.exrx.net/WeightExercises/DeltoidAnterior/BBShoulderPress.html

Check out this site too:

http://www.bsu.edu/webapps/strengthlab/home.htm