You might have already tried to log in to Twitter. If you haven't, but know you forgot your password, open your browser and visit www.twitter.com.
Following similar lessons from logging in, click the blue box at the top right of the screen. After suffering the indignity of a log in, or recognizing that you've forgotten your password, click FORGOT YOUR PASSWORD?
Twitter will direct you to the above page. You will need to type your e-mail or Twitter username.
Click SEND INSTRUCTIONS.
Twitter will let you know if your information is on file. If not, you won't see the above confirmation and will be asked to provide your information again.
Check your e-mail. A message from Twitter with information for resetting your password should arrive soon. Follow those instructions to reset your password.