Twuffer is a web site currently in beta that allows you to schedule Twitter messages (tweets) for delivery at a future date. At present you can only schedule delivery up to 24 hours into the future (the limit appears to be 11pm on the day you are entering in the Tweet). This service is useful for people who are heavy Twitter users wanting to create the impression that they never sleep. Then again, heavy Twitter users probably never do sleep! There’s no registration required. Sign in with your Twitter user name and password and start tweeting while sleeping.