I\'m a Mac user and I\'ve decided to learn Emacs. I\'ve read that to reduce hand strain and improve accuracy the CTRL and CAPS LOCK keys should be swap
The other answer was very complete, but additionally I'd mention I just set the caps lock key to a second control key instead of swapping them.
Also, you'll notice that the large majority of the text entry fields in Mac OS X already accept emacs keystrokes (^A beginning of line, ^E end of line, ^P, ^N, ^K, ^Y, etc)
good luck