According to Norwegian TV, this is the YouTube manifesto of Anders Behring Breivik, the suspect charged with killing over 90 people in two coordinated attacks in Norway yesterday. Be warned: it contains extremely racist content.
There’s also a written version; it runs over 1500 pages, and you can read it here. It’s by “Andrew Berwick” (also the name of the YouTube account, “BerwickAndrew”), which could be an anglicized version of Breivik’s name. Both detail Breivik’s extreme-right, anti-Islam and anti-immigration views.
The video and document have not been officially authenticated, but as noted here, if it was a fake, it would be an impressively detailed one.
Breivik is currently in custody and has been charged with crimes related to terrorism; the charges may change. He has “confessed to the factual circumstances” of the attacks, his lawyer, Geir Lippestad, told public broadcaster NRK.