Another good way of finding MP3s (or other formats) is using Google and typing the following:

parent + directory + mp3 + OR + wma+ #dido#

Replace #dido# by whatever artist you wish to find, for example:

parent + directory + mp3 + OR + wma+ #Lamb#

You should get plenty of dirs with MP3s or WMA files (you could add OGG, etc, to the query). Cheers.