"What is a word cloud?", you may ask. Simply put, a word cloud is a visualization of word frequency in a given text as a weighted list. The more often the word appears in the given text, the larger the word appears in the cloud.
Wordle is a nifty tool that allows anyone to easily create word clouds. Available at http://www.wordle.net, Wordle can be used to create custom word clouds that are limited only by your imagination!
The Wordle website provides a variety of methods for providing the text to be "wordled". The text can be pasted from the clipboard, referenced as an Atom or RSS feed, or linked from a del.icio.us user tag list.
The resulting Wordle is created completely client-side (on your browser) using an imbedded Java applet. A series of drop-down menus allow an amazing amount of customization to be applied to the word cloud. The font, color, layout, and even number of words displayed are all editable.
One down side of Wordle is that there isn't an easy way to save a Wordle creation as an image. Java doesn't have any provision for saving images. Images can either be saved as screenshots, or saved as a PDF through the use of a PDF printer driver like CutePDF Writer (Windows) or cups-pdf (Linux).
Head on over to the Wordle website and give it a try. I'm positive you will soon be addicted!