Twitter SMS Service enables you to stay up to date with commentary by who you care about, to comment back, and to update your account instantly.
Through SMS messages, Twitter gives you the opportunity to follow news from famous personalities you like, news channels, and many more interests.
Twitter is not only a social network, but also a micro-blogging network that allows you to share important moments to you. These short messages (not more than 140 characters) appear to your 'followers' on their site, or in the form of SMS messages.
Subscription and use of the Twitter SMS service is done on your Twitter page at www.twitter.com through the 'Settings' option then clicking 'Mobile' and entering your number and country. Finally, SMS the word 'GO' to 840404.
Upon successful subscription, you'll receive a welcome SMS, and you can then start exchanging messages and receiving notices through Twitter.
Receiving messages and notices from Twitter is free, and 'Tweeting' your own messages costs the same as a regular message sent from your mobile. Subscription, however, is free of charge.

To cancel the service, send an SMS to 840404 containing the code 'unsub'.
You'll receive an SMS confirming your cancellation