You are correct that GPS is 'free' (well, we all pay taxes).
For $10, AT&T will hook you up with TeleNav... a GPS based navigations service... but for free you could use Goggle Maps, Windows Live Search or any of a number of other 'free' GPS mapping services. TeleNav includes voice navigation vs the visual only navigation of Google Maps or the others.
EDIT: wow, you have to be pretty quick around here or someone will beat you to the answer
