Open a new text message on your phone.
Twitter users can receive "tweets" through a computer or phone. Any phone can receive tweets via SMS, as long as it accommodates text-messaging. Twitter doesn't charge for sending tweets to phones, but the user's cellular carrier may charge for receiving text messages.
In the "To:" field, type the Twitter short code for your country. The United States short code is 40404. (See Resources for other country codes.)
Type the word "START" in the body of the message and send it. You will receive a message welcoming you to Twitter.
Reply to the message with your Twitter password in the body. Wait for a second text message from the Twitter system.
Reply to the message with "OK" in the body.