The following maps are provided by each carrier to depict approximate coverage areas.  Actual coverage may vary due to terrain, weather, signal strength, customer equipment and many other factors. Clarity and reception may be diminished by obstructions such as buildings and foliage.  Carriers cannot guarantee coverage, however, it is our mission to help them augment drive and network testing equipment to help identify unknown persistently poor in-building and outdoor coverage areas.    Consumer Reports Summary 

What you should know about wireless phone service FCC.gov

Verizon
Cingular
Sprint/PCS
T-Mobile
Nextel
Alltel
Cellular One
US Cellular
Cricket Comm
Qwest Wireless
PSC Wireless