I cannot get the stock safety out of the rifle.  I have the rifle cocked and in 'fire' position (as described in arfcom's assembly FAQ) but it will not budge with a hammer and punch.  THANKS IN ADVANCE!

Slowly remove the pistol grip.  

On the top of the ejection side of the grip will be a spring (in a hole on the grip, and directly above the spring in the receiver, the selector detent pin that is retaining the selector in place.  
[img]http://www.ar15.com/content/docs/assembly/lower/pistolGrip.gif[/img]

Just a tip, when re assembling the selector it helps to put a drop (dollop?) of grease into the selector spring tunnel in the pistol grip and then insert the spring. The grease will hold the spring in place when you invert the pistol grip to reinstall it onto the lower.

If you have trouble getting the pistol grip screw in place (sometimes playing "Bombardier" doesn't work well) you can bend a piece of thin wire into a tool to lower the screw into place.

Depending on the fit of the pistol grip screw to its hole, a little Blue LocTite is not a bad idea.