A neat trick that was hanging around the Internet but that I found in Transnets. How to search with Google for the MP3 files of your artist of choice. Use the following search phrase (replacing Roumazeilles with the artist name):
{-inurl:(htm|html|php) intitle:"index of" +"last modified" +"parent directory" +description +size +(wma|mp3) "Roumazeilles"}