Twitter is a free social-networking and micro-blogger service in which users can send updates and read other users' updates. These updates are called "Tweets" and are limited to 140 characters. If you are new to Twitter, you may need a little help posting your first Tweet after setting up your account.
Go to twitter.com and log into your account.
Click the "What's happening?" box and type what you want to include in your Tweet. If your Tweet is more than 140 characters, it will be truncated after the first 140 characters.
Click the "Tweet" button to post your Tweet. It will appear on your profile in the timeline for all your followers to see.