Coverage? Know before you go, coverage map 4G, 3G.

Coverage? for iPhone & iPad

Coverage provides an at-a-glance "universal"  data coverage map by interactively overlaying four major nationwide USA cellular providers. 

Coverage focuses on helping bandwidth junkies know where they might be able to get their next hit, no matter what network (or combination of networks) they use. 

Bask in the joys of mobile bandwidth while avoiding the sorrows of data roaming usage caps and absent signal.

Use Coverage to determine which direction is best to head towards, or which route is likely to keep you the most connected in your travels. Know before you go: Avoid having to check each provider's coverage map individually to know where you're most likely able to keep connected in your travels. No internet needed: All coverage maps are stored locally, so you can check where coverage is most likely even when you have none.

Urban and rural areas: Maps cover the entire continental USA, Alaska, Hawaii, Puerto Rico, and the US Virgin Islands for AT&T, Sprint, Verizon and T-Mobile. ('Coverage?' is not intended to give within-city level details - it's goal is to provide an overview while traveling) Know where to roam: view 4G, 3G, 2G and roaming areas as separate overlays, focus on finding the coverage type you need.

Check out their Coverage Map to learn the story behind Coverage, and for a quick video demo.