These are the best resources I've yet to see that explain what wikis and blogs are in a non-technical, easy to understand way. The technique of using paper cut-outs to teach is exciting in itself. Not only will I share these with students, but, with colleagues as well.
Great video on wikis, what they are and how to.
http://www.commoncraft.com/video-wikis-plain-english
Fantastic video on blogging
http://www.commoncraft.com/blogs
http://www.commoncraft.com/blogs
Video on RSS Feeds from same individuals
