The plan itself shouldn't change, since none of AT&T's other phones that have 3G use a different plan package.
Mostly the charge would be from turn by turn directions service (with voice).
Everything else should remain the same.
Does anyone know if Edge is going to default 3G? If you look at the 3G availability map, it is extremely patchy and actually not even available in my area.
So if you don't have it in your area or are driving in and out of availability areas, are you left with nothing? Relying on only wifi would definatley cause some great frustration.
unless they GREATLY improve the 3G coverage in a really short period of time...
No, and here is why. Because that would be retarded.
It will most likely detect a 3g network and use it over edge but where 3g is unavailable it will fall back on the edge network.
I do hope however that even when in a 3g network area you are able to manually toggle between edge and 3g. You know, in case youre not doing heavy browsing and don't want to drain your battery, I've heard 3g is a batt hog.