To send a text message from a computer, log into one of the various Internet instant messengers from the computer, and start sending text messages. The instant messengers that offer this service include AIM, Yahoo! Messenger and Google Talk.
The exact directions for sending a text message from a computer depend on which instant messenger is used. In most cases, the option to send a text or SMS message can be selected from a drop-down menu. With some instant messengers, pressing Alt+T accomplishes the same goal. Many people choose to send text messages via computers instead of their phones in order to save money on their cell phone bills.