Help for a Presentation

I have been asked by my executive director at my school Faith Lutheran Jr/Sr High School to do a 45 minute presentation on Web 2.0 in the classroom. Right now very few of our teachers are blogging and using Web 2.0 tools in their classes, and we are starting a huge technology program. With this type of audience I don't know were to start. I could really use some suggestions and help with this presentation. Any comments/resources from the experts would be appreciated.

Thank you,
Jonathan Orr