I don’t have the 3G model but that didn’t stop Google Maps from being super useful when using their targeting function. If you are in Maps and press the targeting button in the lower left corner, the usual blue circle with inward facing blue tick marks will appear. What’s new (to me at least) is that if you keep driving around, the blue circle will move to reflect your new position. This mode is also shown to be active when the targeting button in the lower left corner stays the bright blue color. Tap that icon once more and the “following mode” turns off. I did notice that I had wi-fi on while I was driving around as well.
I don’t recall this being in the 1.0 Maps app. Maybe I’m wrong. Either way, it’s a pseudo GPS function that is really helpful.
From the newly released iPhone manual it states:
If you have an iPhone 3G, a blue marker indicates your location when GPS is used
to find your location. Otherwise, a circle is used to show your approximate location.
As you move around, iPhone updates your location, adjusting the map so that the
location indicator remains in the center of the screen. If you tap again or drag the
map, iPhone continues to update your location but stops centering it, so the location
information may move off the screen.
I’m not sure if that entire paragraph applies only to the 3G model or both.