See that dark blue blot surrounding Denver, Colorado? That's what a strong 3G cluster looks like on AT&T's Coverage Viewer, and you'll find that kind of concentration around the major cities in the US. The lighter blue spots represent AT&T's EDGE network, which the current iPhone already uses, and the fainter crosshatching and the empty vanilla sections, unfortunately, represent areas where you'll get poor data coverage to squat. So if you live in a rural area of the county and still love gadgets — we know you're out there — the 3G iPhone may not be the phone for you.

Before you buy an iPhone, it's important to know whether you'll be able to take advantage of all of its features or not — especially with the new 3G model. The viewer shows both voice and data on seperate maps and, while they are roughly the same, make sure you find out how your area looks on all of the maps before jumping into a 3G iPhone purchase.

Via AT&T Coverage Viewer

CORRECTION: As reader pixxan pointed out below, I was looking at a map of AT&T's voice coverage — right after warning you not to make the same mistake. The article now correctly references AT&T's nationwide data network, and the original shot of the voice map is included below.