Anagramarama is a free, open source game for Windows, Linux, and BeOS. Best of all, it has a small footprint so it will easily run from a portable drive. If you love games like Bookworm, then you may want to give this game a try.
http://www.coralquest.com/anagramarama/
By the way, the jumble of words in the screenshot does not spell an actual word and it was random.