Tagxedo.com

http://www.tagxedo.com/

This site is similar to Wordle, but you can use a silhouette for the image shape.

Here is a yearbook Tagxedo -  http://www.blogger.com/goog_20756458323



Here is a Tagxedo that I created that uses words from Bloom's Taxonomy  http://www.tagxedo.com/artful/dd1a541216c84e71