www.jimmyr.com is a pretty useful site, he also has some great do it yourself videos on youtube.
His method of using google to download is pretty awesome. It has its limitations of course, but it is brilliant.
http://www.jimmyr.com/mp3_search.php
the instructions are on the screen and are pretty self explanatory.
I ran into his stuff while checking out www.householdhackers.com which is also a pretty slick little site.
I haven't watched the video yet but I know you can do this:
-inurl:(htm|html|php) intitle:"index of" +"last modified" +"parent directory" +description +size +(wma|mp3) "kayne west"
Search for that and it will return servers that allow directory listing and contain the artist you're looking for.