Brian Benzinger's Solution Watch has posted a three part series on Web 2.0 in Education containing the most comprehensive list of web 2.0 style apps I've seen:

• Part 1
• Part 2
• Part 3

It would take days to review all of the applications that Brian has listed. Furthermore, Part 3 provides some how to get started tips and links to resources for using some of the more basic, popular tools (e.g., blogs, wikis, flickr, etc.). This is a great resource to share.