the band nine inch nails and the front man Trent Reznor in recent years have been pro creative commons and open source to promote creation.

on the website they offer up many full master tracks for users to freely manipulate into a new versions using music creation software like garage band or many other open source alternatives.
Internet Memes:
one form of remix culture thats been born through the internet is something called a meme

An element of a culture or behavior that may be passed from one individual to another by nongenetic means, esp. imitation.

one example is "Guile theme goes with everything" where a music sample from the video game street fight II is put with random video clips for amusing results etc...

Pogo is a VJ remix artist that takes samples from films/video and incorperates them into new original music pieces. this is a questionable practise under copyright law.

many believe this is wrong and a new style of copy, copy left was created and much content is now part of creative commons that clearly show what content can be sampled and abused...