TMobile's coverage for prepaid plans. These plans cost at least $0.10/minute (1000 minutes), but are great for people luck me who don't use 'em much. And with the bulk rate, you can roll unused minutes into the next year for as little as $10. Nice!
AT&T's coverage There is a choice for their "GoPhone" which is a pay-as-you go plan, but has significantly less coverage. Though this isn't a problem if you stay in populated areas.