Whats the name of that kungfu movie with all the rappers voices?

Ok probably not Samurai Champloo- that's an anime series,

http://www.imdb.com/title/tt0423731/



Although another anime, if it is anime, it might be one of the Afro Samurai movies.-I really think this is probably what you are looking for.

http://www.imdb.com/title/tt1265998/ or http://www.imdb.com/title/tt1475087/



There's the movie Black Dynamite which is sort of a spoof kungfu movie.

http://www.imdb.com/title/tt1190536/



Then there was a series which was "hip-hop dubbed kungfu"-mainly old Hong Kong kungfu films, mostly black and white, that had been redubbed to make a new story, this series was called Kung Faux.

http://www.imdb.com/title/tt0455262/|||I believe you mean "Samurai Champloo." Well, if not then, then probably something by the same producer/director, as that's nothing except fighting and there's lots of rap on the soundtrack.