Naiyo Humming Music Search is an interesting tool, but you have to be pretty precise about the song you want. I tried Nayio Search with a tune I vaguely remembered, and although it gave me a bunch of results, none of them were of the song I was thinking of.

Instructions on the Naiyo Website:

What is Nayio?

The word “Nayio” (pronounced na-yo) means “my own” in Korean.
Nayio lets you to create “your own” music videos with the free, intuitive Nayio Studio.
With the Nayio Studio, recording vocal remixes of your favorite popular songs, adding videos to your performances
and publishing them to the Web has never been easier!

What can I do at Nayio?

Be the music!
 – Using the Nayio Studio, you can sing, save and share music videos.
   Personalize music with your own vocals, add video or images, then share your performances with the Nayio online community.
   Link to your performances through emails, IMs, or other Web sites like MySpace.
   In addition to music videos, the Studio enables you to create greeting cards and narrated photo albums.

The site is still in beta, and is pretty buggy. However, it’s an ambitious system that would be very cool if it works as advertised, so please let us know about your experiences with it.