Epitonic is a LEGAL website that has TONS AND TONS OF artists mp3's from rock to rap, people that are never heard of and people tht are pretty big in the rock world at elasst (I havent browsed rap)

a few artists I have seen
White Stripes
Beck
Death cab for Cutie
The Yeah Yeah Yeahs
AIR
SIGUR RIOS
Spoon

www.epitonic.com

as far as rap goes the first 3 artists I saw jsut now were
The Pharcyde
Plane Asia
Eminem

SO I think it has good rap selection to