Text messages can be sent to a Cingular phone from a computer by using your email account. It costs you nothing to send an email to a Cingular phone and the person can even respond to your emails. These responses will appear inside of your email's inbox. Due to Cingular merging with AT&T Wireless in 2007, there are two different email addresses for Cingular phones. Which address you use will depend on the person you are messaging.
Sign into your email account. You can use either a work or personal email account in order to email a Cingular phone.
Click inside the "To" (the recipient's) address box on the email page.
Type the Cingular phone number into the "To" box. The numbers should all run together without any dashes or spaces (i.e. 3233233232).
Enter the address "@cingularme.com" or "@txt.att.net" directly after the Cingular phone number (i.e. "firstname.lastname@example.org"). If the Cingular customer has not updated his phone or service since Cingular changed its name to AT&T Wireless, use the "@cingularme.com" address. Otherwise, use the "@txt.att.net" address.
Click inside the "Message" or "Compose" box.
Type in the message you wish to send to the Cingular phone.
Click "Send." The email will be sent to the Cingular phone.
Messages that are 160 characters or longer will be sent to the Cingular phone as two (or more) text messages.
If one of the addresses listed above does not work, use the other in order to email the Cingular phone.
The Cingular phone must be capable of receiving standard text messages in order to receive emailed messages.