Sites to Create Free Educational Wikis:
PBWiki :This is really easy to use. I find it easier to embed non-googley things in a PBWiki. Google Sites has more templates and customization.
WikiSpaces: This is a favorite of many teachers.
WetPaint: Another good Wiki, but not as popular as Wikispaces and PBWiki.
Tutorials about creating Wikis: Creating a Class Website Using Google Sites
This is a comprehensive site with step by step on how to create and use Wikis. In Education. Thanks to Jen Dorman, I won't try to reinvent the wheel.
Examples Using Google Sites
Examples of different ways to use a wiki:
I have a great group of people in my Professional Learning Network. I asked them today to share examples of wikis they have created. Not only are these great examples of wikis, these are also great examples of collaboration.