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.