Beemp3 is a simple mp3 search engine that is very easy to use and comes with a simple design that allows your to search for mp3’s online. The site tells you bitrate and information about the song when you hover over the filename. The results are very relevant and I am not sure if this site will last that long once RIAA finds out about it.

url - http://beemp3.com/

You can also try the following sites for mp3 search -

http://elbo.ws/
http://hypem.com/
http://shareminer.com/
http://www.seeqpod.com/
http://songza.com/