Just found this great little article over at superuser.com about how you can use meta-b and meta-f to use backwords and forwards by words in the CLI. Since there is no meta key, you have to use ?-b and ?-f (escape as meta).
Optionally, you can set the option key as meta in Terminal’s settings:
!http://files.classyllama.com/dec8e77a/terminal-settings-meta-key-20110516-205752.jpg!
