ICT in Education put together this free book "Amazing Web 2.0 Projects." Worth checking out. From their website:
* 87 projects.
* 10 further resources.
* 52 applications.
* 94 contributors.
* The benefits of using Web 2.0 applications.
* The challenges of using Web 2.0 applications.
* How the folk who ran these projects handled the issues...
* ... And what they recommend you do if you run them.
* What were the learning outcomes?
* And did I mention that this is free?!