I wanted to create a tag cloud of my thesis, which is written in LaTeX. This is almost trivial. You can go to Wordle, upload the text, click "Go", and you're ready to go. Except that being written in LaTeX, if you just do that you will see a lot of irrelevant markup (begin, end, includegraphics, etc) words in the word cloud.
An easy way to solve this is to use a program called detex, that transform a LaTeX source document into plain text. All you just need to do is the following:
$ detex -l *.tex > thesis.txt
Since I have the document divided in several files, I need to use the -l option to force detex to use LaTeX mode (without a \begin{document} detex doesn't use this mode automatically). Then you can upload thesis.txt to Wordle and you are good to go.
This is the result: