According to Wikipedia , a Wiki is computer software that allows users to easily create, edit and link web pages. Think of it as an easy way to make a web site, but it is really much more than that. You can set it up to let anyone add content to it from anywhere, or only those people you choose.

Get your own Wikispaces Account!Free Wiki's for Teachers.

50 Ways to Use Wikis for a More Collaborative and interactive Classroom.
Everything you ever wanted to know about Wiki's but were afraid to ask can be found at
Check out this Wikipedia Screencast to learn more about how wiki's work.
Here is Wikispaces great How to Get Started page.
Now look at these great videos on how to get started in wikispaces. Get an Educational Wiki, free with no ads here.

While we use Wikispaces (they give free space, without ads, for educational use), there are many different wiki options available. Which is best for you? One way is to compare and contrast the different wiki's. You can do that at WikiMatrix .

Web 2.0 Workshop

Web Site Good tutorial for Wikispaces.

Teachers First Wiki Walk Through
Create Student Accounts by yourself!

Will Richardson's Wiki -

A Web of Connections: Why the Read/Write Web Changes Everything

Examples of Educational Wiki's

Kirk Guymon, Math Teacher
Southwest Band Wiki
Inspired Classrooms
Westwood High School Wiki
Intro to Computers
K-12 Training
Flat Classroom Project
Horizon Project
Cool Cat Teacher
Computer Kiddos Wiki
Quarter Mile Lane School
5th Grade Greenville, PA

Find a large list here.