Twitter can be a useful tool for a church.  It's a fast, cheap and easy way to send out very short messages.  With Twitter you can read and write messages up to 140 characters long.  That may not sound like much, but it's enough to be of use to you and your church.  Here are a few ideas:

Send out a daily verse that has something to do with the coming message or the previous weeks message.

Send out reminders about events being planned

Send out news from the congregation

How do you use Twitter?  First, you just sign up an account at Twitter.com.  Then anyone in your church (or anyone in the world) who has a Twitter account will be able to follow you, that means your tweets (messages you send out with Twitter) will be visible to those people.  Your Twitter followers will be able to see your messages either by logging in to Twitter or they can connect their Twitter account to their cell phone or various other social networking tools.