http://www.teachersfirst.com/content/wiki/
It is a living collaboration whose purpose is the sharing of the creative process and product by many.

In K-12 education, wikis are being used by educators to conduct or follow-up after professional development workshops or as a communication tool with parents. The greatest potential, however, lies in student participation in the ongoing creation and evolution of the wiki.

http://www.teachersfirst.com/content/wiki/wikiideas1.cfm
Tons of ideas for how to use wikis
Creating an organizational structure for the content is an important part if the project.

http://jdorman.wikispaces.com/space/showimage/Wiki+Wisdom+Article.pdf

http://www.wikispaces.com/site/for/teachers100K

http://www.wikispaces.com/help+teachers

http://educationalwikis.wikispaces.com/

http://jdorman.wikispaces.com/digitalstorytelling

http://drcoop.pbwiki.com/Wikis
http://wikisineducation.wetpaint.com/?t=anon

http://www.wikieducator.org/Wikis_in_elementary_schools