As a professor of education, I believe that teachers-to-be must be savvy users of online technologies in order to be effective classroom teachers. I give my students ample opportunity to create and collaborate through Web-based tools. Here's a list of my favorites:
Use this tool for collaborative essays and other document writing. Among other things, Google Docs lets me provide in-process feedback and advice to teacher-education students as they work on papers or research reports.
I'm often surprised at how few of my teacher-education students are aware of this specialized search engine for research reports and academic articles. If a student sets up the preferences to include her university's library, she can have Google Scholar also search that library's online, full-text article databases.
Collaborative blogging as a class generates a sense of shared purpose. As a bonus, I often discover really useful, new resources through links my students post.
This site offers shared bookmarking. Teacher-education students can subscribe to my set of bookmarks and gain a whole stack of resources from day one. Plus, they can share with one another what they find along the way once we've set up a class network.
This site and its learning section cover copyright issues and how teachers can address this topic in their classrooms, both by understanding what's at stake if copyright laws become too all-encompassing and how important it is to respect and protect artists' original work. We focus on learning how to read Creative Commons licenses and use resources bound by such licenses in informed ways. Within the Creative Commons online suite, we make use of resources such as ccMixter, which gives us access to music and songs that don't fall afoul of music companies' copyright laws. Wikimedia is another excellent portal to fair-use resources.
This is a free wiki platform. Wikis are excellent for creating sustainable professional-development spaces that extend beyond the university walls and continue on after graduation from our programs.
This site offers a public space devoted to fan-fiction writing and reviews. I don't require students to write their own fanfics, but many choose to do so and really come to understand how fan-fiction writing and reviewing develops important narrative skills and processes not often well addressed in classrooms.
This site helps people create how-to tutorials for using online resources. Alternatively, educators can download a free version of CamStudio for PCs, a trial version of Debut for PCs, or a trial version of iShowU for Macs. You can use these applications to record all sorts of on-screen action, and they are very useful for creating short movies you can edit with Windows Movie Maker or Apple iMovie.
Use this site for collaborative storytelling or document annotation.
I've been involved in developing this professional-development literacy 2.0 wiki for middle school educators as part of a project to help improve the teachers' digital-literacy work in schools that serve low-income communities.
And, of course, you can use YouTube and Flickr, the giants of video-sharing and photo-sharing sites respectively. I also direct students to KeepVid, a service for downloading YouTube videos to your hard drive, and Zamzar, for converting video-file types.