I just discovered this wiki, TwitterEd via a tweet from rkiker this morning. It has loads of examples and ideas for using Twitter in your classroom. The ideas are innovative and demonstrate the reach and power of a PLN (Personal Learning Network) that teachers around the world are finding indispensable.
As someone who is relatively new to Twitter, I say, with absolute conviction, that Twitter has become an invaluable tool in my own professional development. I tweet to learn, in other words. If you are considering using Twitter but can't quite figure out its place in your classroom, this is where I'd start: Tweet to learn. Find experts in your discipline, follow them, and share these tweets with your class. I've found that these tweets are sometimes just a comment, but more often contain a link to a treasure chest of resources (see above). As a Moodle school, we can pull a Twitter feed into our course pages where students have access without setting up an account.
To really appreciate the power and reach of Twitter, however, teachers need to build a personal learning network. Your reach is determined by the number of people following your tweets. Currently I have 38 followers and many are groups or organizations (NAIS, Edutopia, etc.) Yes, I follow teachers, really smart ones (suludavis, larrykahn, zandrews, smcmanus, rkiker), but I know that to extend my reach, to become a truly "connected educator," I need to to expand my list of followers. I want a global reach, not only for myself, but for my students too, because my network benefits them. Take a look at the examples in TwitterEd. A teacher sends out a "calling all experts" tweet and students are lifted out of the classroom, provided links to rich resources, and challenged to question, think, research, and respond (via the teacher's account for younger students) to real people, in a meaningful way. Connected teachers connect their students to other students to collaborate and create with one another without the limitations of time and space. This is my goal for the year: expand my network, expand my reach, expand my (and my students') opportunities for learning.
At Alan November's BLC Conference this summer I attended a session given by Jeff Utecht (jutecht), the Technology & Learning Coordinator at the International School Bangkok. He said that when he was being interviewed for the position he was asked what he would bring to the school? "6,794 people from around the world" who he could reach out to on behalf of the students at ISB. When Jeff sends out a tweet to ask for help or to share something his students have accomplished, people are listening and responding. It's no longer just what you know, it's who and how many people you bring with you into your classroom.