With Wordle you can compile images of words that you can either type in, cut and paste, or you can also use web pages by entering in the URL. You can then format the layout, colors and edit language settings to put together interesting visual aids for learning vocab, reviewing main words from texts and all kinds of uses in your lesson plan.
Wordle is free, but it isn't as easy as simply saving the images as a .pdf or .jpeg file. Since it generates images with Java, you'll need to take a screen shot of the image and edit it down, or use the handy code that they provide you to directly post the image in your blog or on a webpage.