Here is a list of examples of Blogs and Wikis being used by educators in ways that enhance instruction:

Student work

http://buckeye.learnerblogs.org/

Mighty Writers

http://classblogmeister.com/blog.php?blogger_id=5655

Wells Elementary Computer Lab

http://classblogmeister.com/blog.php?blogger_id=11114

Bishop Dunne 304

http://classblogmeister.com/blog.php?blogger_id=21053

English Corner

http://classblogmeister.com/blog.php?blogger_id=17192

Professional Development

David Warlick

http://davidwarlick.com/2cents/

Mark Ahlness

http://www.halcyon.com/arborhts/mahlness/

Room 208

http://www.bobsprankle.com/blog/

Educational Wikis

Elementary All Stars

http://elementaryallstars.wikispaces.com/

Penn State

http://mitochondriac.pbwiki.com/

Vicki Davis

http://coolcatteacher.blogspot.com/2005/12/wiki-wiki-teaching-art-of-using-wiki.html

Vicki Davis-teaching wiki

http://westwood.wikispaces.com/Web+2.0

Choose your own adventure

http://terrythetennisball.wikispaces.com/

Houghton Mifflin Lessons

http://hmtech.wikispaces.com/