Internet Anagram Server, also known as "Isn't re-arrangement rave?" and "I, Rearrangement Servant".
One of the world's most widely known anagram generators.
It can be found at
http://www.wordsmith.org/anagram/ - they also have a just plain hilarious "Hall of Fame" of cool anagrams.
"All the life's wisdom can be found in anagrams. Anagrams never lie." - Anu Garg, creator of IAS ("Name is Anu Garg" == "Anagram Genius")