Just unleashed Twitter with my students last week.
I say "unleashed" because as a teacher I am finding it to be a fantastic tool for developing ideas and exploring new tools. I have a separate twitter account that I use to follow inspiring teachers and educators around the world, such as @infernaldepart, @deputymitchell and @derekrobertson. These teachers are across all key stages and subject areas which makes it more exciting to see how they are developing teaching and learning within their own specialism. I have been using my iPad to access Twitter and I have it installed on my Blackberry. At times I can't put it down, even when the football is on.
There are so many useful discussions taking place such as #ukedchat and #ictcurric.
I am currently developing the use of Twitter with my Sixth Form ICT class. I have set an separate account and list to keep our tweets private. The whole idea is that they can share resources, links or ideas and also seek help or support when needed from their peers. I have only began to scratch the surface of how it can be used and can't wait to see how much more the students can do with it!