I just had been toying around with Wordle - a website which allows you to quickly generate fairly flexible word clouds to visualize arbitrary textual content. I am currently looking into ways to visualize content (mostly based on textual models of course). There is another resource I'd like to share. A very powerful layout engine which can be used within have is prefuse, its API is very easy to understand and fairly well documented. Check out the gallery, if you'd like to know more.