This thread really should be locked, since there is no Hot Deal to be found in it.
That aside, I'd like to correct some info in drue's largely informative post.
Sprint PCS and Verizon *do* use different frequency bands. SprintPCS was built from the ground up on 1900 MHz PCS. Since they have PCS coverage in only the major metro areas, they partner with other carriers to provide service to their customers in Roaming Agreements. To this end, a SprintPCS phone can actually switch frequencies to 800 MHz (in the US) and borrow another network. On 800 MHz, the phone can be either CDMA digital, or old-school AMPS analog. Some phone models support all three modes ("Tri-Mode") while others are digital-only, and do not support 800 MHz AMPS. I don't think SprintPCS sells any true 1-band 1900 MHz phones, but they did have them during their rollout (QCP-1900 model). Obviously, Sprint would rather you use the 1900 MHz band, so the program the phone to prefer it, sometimes agressively.
Verizon is largely a conglomeration of older phone networks that date back to the 800 MHz Analog (AMPS) network. On AMPS, there were two carriers in each market (A & B, non-wireline, wireline). Verizon has upgraded almost all of the networks to be 800 MHz CDMA digital, so the same frequency can usually carry either kind of call. They very much discourage AMPS connections, of course, since it uses more effective bandwidth on the air.
Some Verizon phones can roam onto the 1900 MHz PCS frequency, but to my knowledge, they do not permit this -- it is locked out through phone programming.
In my experience, Verizon's signal does have better penetration than the higher-frequency SprintPCS, due to both basic physics, and a 20-year lead on installing cell sites and leasing property.
In some places, SprintPCS has teamed up with cable television providers to distribute their signal, but there are still large dead areas and frequent dropouts. I carry both a Sprint and Verizon phone when I travel, and find that the Verizon phone often has coverage when the Sprint is searching, but very rarely the other way around. In rural areas, the Sprint phone is a longshot.