For years cellular phone carriers have misled people about their coverage maps. Radio Shack used to feature Sprint PCS in their stores, and I had a lot of fun telling young enthusiastic sales clerks that the claimed coverage was a pack of lies.
Carriers like to publish "approximate" coverage maps. T-Mobile has broken the mold: they've published detailed street-level maps showing exactly what coverage you get.
This is a bold move. T-Mobile uses superior technology -- GSM, the standard used across Europe and much of the world -- but their coverage in the U.S. is poor compared to, say, Verizon. (By the way, T-Mobile is not Catherine Zeta-Jones; it's Deutsche Telekom.) It will be interesting to see if competing carriers have the guts to pony up the truth about their coverage.