The following is the list of carriers that we support (updated 9/10/08)…

United States (and Puerto Rico)
Alltel
AT&T
AT&T (Cingular)
Bluegrass Cellular
Boost Mobile
Cellcom
Cellular One
Cellular South
Centennial Wireless
Cincinnati Bell
Cricket Wireless
Metro PCS
Nextel
nTelos
Pioneer Cellular
Qwest
Sprint
SunCom
Thumb Wireless
T-Mobile
Unicel
United Wireless
US Cellular
Verizon
Virgin Mobile

Canada:
Bell Mobility
Fido
Rogers Wireless
Telus
Virgin Mobile (CA)

If you don’t see a carrier listed, please send an email support@txtsignal.com. We will have most carriers added within 24 hours.