"AGPS devices use traditional GPS receivers, but help speed up location acquisition and accuracy by using cellphone towers to triangulate".
iPhone 3G = AGPS, but can also use WIFI as locator.
"Location-aware smartphone — not a dedicated GPS device." 3rd party software on the way though to give car gps like functions. While it only takes the iphone a few seconds to get location that may be an issue when driving fast?