Rapmusic.com is a very well-laid out, easy to navigate cornucopia of information about Rap and Hip Hop music. As I know next to nothing about these types of music, if I needed information, I'd probably look here. There's tons of reviews, news, information on loads of artists, various sub-genres as well as very active messageboards with a wide range of subjects from DJ'ing to Emcee battles to production to more general music discussion.

A great site!