If you want to generate word clouds, Wordcram is the perfect program for this. Easy to use, beautiful and flexible, it lets you the liberty to analyze any text and transform it in revealing, silly, beautiful and interesting word clouds.
A big advantage of this program is the fact that is completely free. It is also open source, so you can help mak it better if you know how and you want to. If you are a simple user, it is easy to install and has lots of tutorials and examples you can use. If you have any problems, there is a FAQ with almost every answer you need.