Taking a move out of T-Mobile's playbook, Sprint Nextel has launched detailed coverage maps. Instead of just providing general maps (usually based on region or at best market), you can now input an address and see coverage in a specific location. T-Mobile launched a similar service about a year and a half ago.
Power Network Coverage Tool (as it's called) shows street-level coverage for both voice and data (EV-DO). It's available online or at kiosks in Sprint retail stores. The tool also includes coverage for Nextel's network.