Word Smith, Word Plays and Future boy all have good anagram generators on their websites. Anagram Genius also has a good anagram tool and offers a free downloadable version.
Anagrammer, the anagram generator by Word Plays, creates anagrams by rearranging the letters in a given word or phrase. Anagrammer uses all of the letters in whichever word the user supplies. Future Boy also offers an anagram generator, and offers a wide variety of options for returned results, such as crossword dictionary, compound words and female names. Future Boy's anagram generator also lets users choose the maximum word length of their anagram.