Note: This was an experiment to see if javascript could be fast enough to do this sort of thing. It was never finished. The count of anagrams should be updated and the crossword finder should be hooked up. Feel free to take it and hack on it if you like.
It encodes a dictionary of 106,495 words (an old Scrabble dictionary) into 427,982 base64 characters.
http://www.davidst.com/jsanagram/