Tagul is a new site (beta) I just learned about from another excellent blogger & technology pioneer, Alexandra Fransisco. Tagul is very similar to Wordle except that you pre-determine what shapes you want to use then just enter a URL of a site you want to "cloud". You do not type in your own keywords that you do in Wordle.
The only drawback I see on this site is that there is no built in filter, but w/ appropriate district AUP guidelines it should be ok to use.
Give Tagul a try by clicking here.
Below is my example of tagging this very blog...