Ohhla.com is the original hip-hop lyric archive, the largest, and perhaps only, compendium of rap lyrics on the internet. All genres and sub-genres of hip-hop are included, from the commercial to the underground. In all, probably 300 artists, around a 1,000 albums and several thousand songs are detailed on the site.
The only problem with the site is that since archiving hip-hop lyrics is not exactly a money making activity in and of itself, there is a lot of banner ads that have to be navigated. Other then that though, it is a fine place to go to finally straighten out whether the RZA is talking about mysticism, Mathematics or street life (or maybe all three).
The site is run by one Steve 'Flash' Juon, a frequent contributor to rec.music.hip-hop.