Each week, I'm going to highlight a different Web 2.0 tool, and give some ideas on how to use it in the classroom. I will only discuss tools that I have tried in my classroom and have found to be useful.
Tech Tool - Screenr - A Screencasting Tool
*Update 3/21/13 - Screenr is still one of the easiest to use, but I have switched to using Screen-cast-o-matic, as it allows longer screencasts(up to 15 minutes with the free version, and unlimited with the pro version! Here's a sample of one those screencasts: