http://www.wordle.net

Wordle allows the easy creation of beautiful word clouds from any text. Word clouds are a means of displaying text is a visual manner, where the frequency of use of a word determines its visual prominence. A great way to use word clouds is to create one as a primer to a text that is to be studied: this can be used to learn vocab ahead of time, or to try and guess the meaning and content of a text based on a single dimension. The uses for word clouds are practically as limitless as your own imagination.