CC has added a new symbol for Wikis. The CC-wiki license is simply a Attribution-Share Alike 3.0 Unported License.

What this means is that anyone can use wiki material under a cc-wiki license as long as you:
1. give credit and
2. use the same license on derived future works

This wiki is licensed under a
Creative Commons Attribution-Share Alike 3.0 Unported License.
The Image looks cool, we might have to use it on our upcoming wiki.