Fixing Emacs 23 on Mac OS X
If you are a long time emacs user and upgraded to release 23 on Mac OS X. You will find that your command and option keys are changed and fn- left/right no longer functions as beginning-of-line and end-of-line respectively.
Switching them back is as easy as,
(setq mac-option-modifier 'super )
(setq mac-command-modifier 'meta )
(define-key global-map [home] 'beginning-of-line)
(define-key global-map [end] 'end-of-line)