AcademHack has a great article on the use of twitter in schools… check it out!

Ideas from the article:

• Class Chatter
• Classroom Community
• Get a Sense of the World
• Track a Word
• Track a Conference
• Instant Feedback
• Follow a Professional
• Follow a Famous Person
• Grammar
• Rule Based Writing
• Maximizing the Teachable Moment
• Public NotePad
• Writing Assignments

Another thing which may be of interest… 7 Things you should know about Twitter from Educause.