cr3ation b3ta has a great music search engine.
It not only searches for music, it filters out fake/broken links.

Not that I ever have too much trouble finding anything I’m looking for, but I’ve been using google for a long time to do “index of” searches. I never thought to set a keyword search in Firefox though. Using this url for your index of keyword bookmark search.

Then in your address bar, type something like “mp3 playradioplay”

Enjoy!

I just remembered this website that does all the work for you: http://www.g2p.org/