This isn't really a review as it is mostly an overview of US regional GSM operators. Most (if not all) have agreements with major nationwide operators for roaming. If you are a student or a local resident you might find some of these operators useful if you are looking for a plan. Also useful if you are travelling in a specific area and you wish to get a local SIM for your collection (if you collect such things).
Network: First Cellular
Region: Southern Illinois
Partners: ???
Prepaid Name: Funtalk and Unlimited Prepay
Website: http://www.firstcellular.com/pages/r....php#nav_cont5
Network: Amerilink
Region: Northern Texas
Partners: ???
Prepaid Name: ???
Website: http://www.amerilinkpcs.com/
Network: CellularOne
Region: Illinois
Partners: ???
Prepaid Name: on the go
Website: http://www.cellular1.net/prepaid.htm
Network: Chariton valley
Region: North central missouri
Partners: ???
Prepaid Name: ???
Website: http://www.cvalley.net/CVWS/chip.htm
Network: Cincinnati Bell
Region: Ohio
Partners: ???
Prepaid Name: iWireless
Website: http://www.cincinnatibell.com/reside...eless/prepaid/
Network: Edge Wireless
Region: Oregon, California, Wyoming, Indiana
Partners: AT&T
Prepaid Name: ????
Website: http://www.edgewireless.com/products/rate.html
Network: Einstein PCS
Region: Wisconsin
Partners: ???
Prepaid Name: Big Talk
Website: http://www.einsteinpcs.com/airadigm/prepay/default.asp
Network: Iowa wireless
Region: Iowa
Partners: T-Mobile
Prepaid Name: MEGAtalk
Website: http://www.iowawireless.com/megatalk_payinadvance.asp
Network: Immix
Region: Pennsylvania
Partners: ???
Prepaid Name: Prepaid
Website: http://www.immix.com/_page/rate_prepaid.htm
Network: OneLink
Region: Illinois
Partners: ???
Prepaid Name: Pay as you go
Website: http://www.onelinkpcs.com/prepaid.html
Network: Corr Wireless
Region: Alabama
Partners: ???
Prepaid Name: Prepaid
Website :
http://www.corrwireless.com/prepaid.html
Network: Westlink
Region: Kansas
Partners: ???
Prepaid Name: SNAP
Website: http://www.westlinkcom.com/snap.htm
Network: SunCom
Region: North Carolina, South Carolina, Virginia
Partners: AT&T
Prepaid Name: ???
Website: http://www.suncom.com/
Network: Epic PCS
Region: Kansas
Partners: ???
Prepaid Name: Prepaid
Website :
http://www.epicpcs.com/
Network: Indigo Wireless
Region: Pennsylvania
Partners: ???
Prepaid Name: ???
Website: http://www.indigowireless.com/gsm.htm
Network: Alaska Wireless
Region: Alaska
Partners: ???
Prepaid Name: ???
Website: http://www.prepaidgsm.net/en/usa/alaska.html
Network: Dobson
Region: Oklahoma
Partners: ???
Prepaid Name: ????
Website: http://www.dobsoncellular.com/
Network: PSC wireless
Region: Georgia
Partners: ???
Prepaid Name: SmartPay
Website: http://www.dobsoncellular.com/
Network: Unicel
Region: New Hapmshire, Maine, Vermont
Partners: Cingular/T-Mobile
Prepaid Name: SmartPay
Website: http://www.unicel.com/zone46/store/service/step1a.html#