highlight any text on any web page, click a capture button to save it in a virtual notebook, and view all of their highlights from across the web. Citelighter automatically puts together a citation page.
Great session by Hella Rumschlag and Laurie Loughery of Mohawk Trails Elementary. Their project involved collaborating with schools across the country using various web 2.0 tools
Simple K-12 periodically offers some free webinars on web 2.0 topics (of course, trying to entice people to become subscribers), but even the free ones include some great presenters and topics
Lots of great ideas here from Karen Ault. "The Web in My World" is one of her presentations.
There are many, many suggestions and tips under the various categories. This can't do justice to all that she's shared, but it's a starting point!