Put the number before the appropriate carrier:
Alltel [10-digit phone number]@message.alltel.com
Example: [email protected]
AT&T (formerly Cingular) [10-digit phone number]@txt.att.net
[10-digit phone number]@mms.att.net (MMS)
[10-digit phone number]@cingularme.com
Example: [email protected]
Boost Mobile [10-digit phone number]@myboostmobile.com
Example: [email protected]
Nextel (now Sprint Nextel) [10-digit telephone number]@messaging.nextel.com
Example: [email protected]
Sprint PCS (now Sprint Nextel) [10-digit phone number]@messaging.sprintpcs.com
[10-digit phone number]@pm.sprint.com (MMS)
Example: [email protected]
T-Mobile [10-digit phone number]@tmomail.net
Example: [email protected]
US Cellular [10-digit phone number]email.uscc.net (SMS)
[10-digit phone number]@mms.uscc.net (MMS)
Example: [email protected]
Verizon [10-digit phone number]@vtext.com
[10-digit phone number]@vzwpix.com (MMS)
Example: [email protected]
Virgin Mobile USA [10-digit phone number]@vmobl.com
Example: [email protected]
Alltel [10-digit phone number]@message.alltel.com
Example: [email protected]
AT&T (formerly Cingular) [10-digit phone number]@txt.att.net
[10-digit phone number]@mms.att.net (MMS)
[10-digit phone number]@cingularme.com
Example: [email protected]
Boost Mobile [10-digit phone number]@myboostmobile.com
Example: [email protected]
Nextel (now Sprint Nextel) [10-digit telephone number]@messaging.nextel.com
Example: [email protected]
Sprint PCS (now Sprint Nextel) [10-digit phone number]@messaging.sprintpcs.com
[10-digit phone number]@pm.sprint.com (MMS)
Example: [email protected]
T-Mobile [10-digit phone number]@tmomail.net
Example: [email protected]
US Cellular [10-digit phone number]email.uscc.net (SMS)
[10-digit phone number]@mms.uscc.net (MMS)
Example: [email protected]
Verizon [10-digit phone number]@vtext.com
[10-digit phone number]@vzwpix.com (MMS)
Example: [email protected]
Virgin Mobile USA [10-digit phone number]@vmobl.com
Example: [email protected]