Sending a text message from a computer to a mobile phone is accomplished using the SMS gateway provided by most mobile phone providers. This free e-mail-to-text-messaging service transfers e-mails to the text messaging inbox of the mobile phone user. In order to use this feature you must know the recipient's mobile phone carrier. The SMS gateway allows you to send text messages and picture or multimedia messages.
Log in to your e-mail account.
Enter the recipient's text messaging inbox address in the "To" field of your message. The text message inbox address is the mobile phone number followed by the gateway extension. For example, the SMS gateway address for Sprint phones is firstname.lastname@example.org. The 10-digit phone number should be listed in place of "mobilephonenumber."
Enter the message you would like to deliver in the body of the email and click "Send." Your message will be delivered to the recipient's phone as a text message.