1.

"making music out of other people's music" 
Hip Hop - A street history  
54min., Directed by Dick Fontaine -

the movie is about where Hip Hop started and the origins of the HipHop culture in the late 70's in the South Bronx/New York City, introducing all elements that represent this music: scratching and cutting, looping breaks with 2 turntables (DJing and turntablism), rapping, human beatboxing, Boomboxes, Tagging and Graffiti, breakdance. Interviews and short statements by Dj Kool Herc, Afrika Bambaataa, Malcolm McLaren, archive footage by Rap Brown, Nelson Mandela, Malcolm X, Muhammad Ali. small 'cameo' performances by Curtis Blow, Arther Baker, Lisa Lee, Jazzy Jay, Mel Brooks and others.

Hip Hop at wikipedia: http://en.wikipedia.org/wiki/Hip_hop
more info about the movie: http://www.imdb.com/title/tt0440086/
online location of this movie: video.google.com/videoplay?docid=3972671039973659170&hl=en#

2.

another great resource of information about Hip Hop is this video with KRS-ONE doing a lecture at the Temple Universicity in april 2004 called:
Hip Hop Beyond Entertainment   April 2004 - A Video by Alex Goldblum. Special Thanks to the Philosopher of Hip Hop, Knowledge Reigns Supreme Over Nearly Everybody www.templeofhiphop.org 

the online location of the KRS-ONE video lecture is here: video.google.com/videoplay?docid=3972671039973659170&hl=en#docid=2210962754622668554

3.

STYLE WARS online 

watch STYLE WARS online here:
www.veoh.com/browse/videos/category/entertainment/watch/v1573689Tm2qDBES

wikipedia info: http://en.wikipedia.org/wiki/Style_Wars

Update "THE STYLE WARS RESTORATION PROJECT": http://www.thedocumentaryblog.com/index.php/2010/05/07/the-style-wars-restoration-project/

URL at Google video: video.google.com/videoplay?docid=3972671039973659170&hl=en#docid=4590872038597640988