I came across this first short list of Web 2.0 tools, broken out by grade, that are specified for the English and Language Arts realm (K-12) and thought I'd share. Of course you don't have to be in those content areas to use and benefit from them though!
I liked the bubbl tool for online brainstorming - easy, fun, and worked well with my kids!
The Acapela tool/site would be great for an English OR foreign language class...
For those of you who are looking for a more extensive list, here is a link to the top 100 Web 2.0 tools of 2011, according to edudemic.com
I KNOW there are some tools on there that you can use in your classroom. Give some a try!