Here is a collection of excellent educational applications of wikis.
Dean
Shareski’s Wiki
Very nice resource on Web 2.0 tools, including wikis.
Dean Shareski's Digital Storytelling Wiki
An example of a wiki used to plan and deliver staff development
Will Richardson's Presentation wiki
Comprehensive Read/Write Resources
Whiplash | Darren Kuropatwa
A collection of useful resources on wikis and other 2.0 tools
Bud
Hunt’s Wiki
Created by Colorado teacher Bud Hunt and many educator-collaborators.
David
Warlick’s Presentation Handout Wiki
A wiki designed to support the presentations of education guru David Warlick
DG
Summit Wiki
Supports a two-day staff development project on Web 2.0 methodologies;
includes participants’ blogs, session podcasts, and handouts.
Educational
Blogging Wiki
Supports the educational uses of blogs and contains links to student and
teacher blogs.
High
School Online Collaborative Writing
Features the collaborative writing of various high school students.
Library
Success: A Best Practice Wiki
A collection of smart practices for libraries and the issues that impact
them.
Mrs.
Davis’ Westwood Schools Wiki
An online space for Westwood schools’ students that includes a variety
of student projects, including an insightful analysis of Web 2.0 tools.
PodcasterCon
wiki
Supports collaborative pre-conference planning for PodcasterCon 2006,
an event for learning about podcasting, and hosts content about each session
that participants can add to.
Swarmsketch
Just for fun: This site allows you to contribute a single line to a drawing,
and then vote for the inclusion of other lines in the drawing.
Wikibooks
Collection of textbooks that can be edited by anyone.
Wikiville
A wiki where students can build stories about where they live.