Web pages with helpful web resources for teachers:

The Digital Backpack is a directory of free web-based tools useful to educators.

Cool Tools For Schools
Web 2.0 tools, organized by category (presentation tools, collaboration tools, etc)

Getting Tricky with Wikis
Tips and tricks for using wikis in the classroom.

Cogs for Blogs
Ideas for using blogging tools in the classroom; looks like the author is focused on offering more specific "how-to" hints on how to use the kinds of tools linked from the Cool Tools for Schools site (above).

The Edublogger
Very specific suggestions on how to use blogs in the classroom, specifically focused on using the edublogs platform.

This list of 2.0 tools and links is a wiki kept up by teachers. There are a lot of cool tools on it, although it is not broken down by categories.

ClassTools is a site where you can create educational computer games for your students. You make up the questions and plug your quiz into a variety of flash game formats! Easy and free.

Cog Dog Roo
This wiki keeps a current list of the top 50 online story tools. Includes links to media presentation tools, voice threads, timelines, audio and video editors, etc. Great resource and up to date.