Collaborize classroom looks very interesting and it's free. Encourages student engagement, shares lesson plans and more. Pretty strong endorsements of website as well. Worth checking out.
PresentationTube Recorder is a tool designed to record Ppts for 15 minutes--free, of course, though there is a paid version that allow more to be done. Worth a look
Zotero allows students to keep track of where they researched; helpful for reference and research puproses. Works with Firefox and can sync. Looks good. Download the app (free).
iPad app for students--you can insert text for students to practice fluency or use as a teleprompter for choral reading. Free, of course, and easy to use.