Maybe someone might have been posted them here before, but I just found them out. Anyway, have a look:
- This is a Prince Naseem highlight, shows him as a kid, his debut fight (a total clown!) etc:
http://video.google.com/videoplay?docid=-4593746314353750079
Then on the same page click "more from this user", there you'll find loads of mma clips plus highlights of Mayweather Jr., Manny Pacquiao, Sugar Ray Robinson, Jack Dempsey, Jorge Foreman etc...