Yes, I do know what assisted GPS means and how it works. It speeds up position locking when turned on significantly. What I don't know is how the iPhone has this implemented. Question: Can the iPhone GPS operate WITHOUT a cellular network. It will take longer, granted, but will it get a fix or not? This is very important, since there is gonna be navigation-Software like TomTom & Navigon. What if you're in an area where there is no service?! If its strictly A-GPS, depending on a mobile network to get a lock at all, it wouldn't work, which would be unacceptable for a navigation-system! There must be some 3G users that have used offline maps or some geocaching app that were out of coverage areas?! Did it work or not?