I haven't tried it yet...but this got my attention.

"Got a song stuck in your head but can't remember its name? This site houses a searchable collection of more than 30,000 tunes, melodies and musical themes. To find a particular entry, you can either enter a keyword or — more impressively — hum part of the tune into the site's interface (via your PC's microphone). Just click on the "Music Search" feature to get started. The success rate is surprisingly high."
http://www.musipedia.org/

Eddie