IGN
Videos, screenshots, cheats, FAQs, preview, news, press release, and a message board.
http://ps2.ign.com/objects/881/881593.html

Wikipedia
Article describing the story, gameplay, and characters.
http://en.wikipedia.org/wiki/Warriors_Orochi

Team Xbox
Provides information, news, screenshots, and a trailer.
http://games.teamxbox.com/xbox-360/1823/Warriors-Orochi/

CCG
Contains lists of unlockable cast members for each of the forces.
http://www.cheatscodesguides.com/playstation-2-cheats/orochi/

GameSpot
News, previews, images, videos, cheats, and a forum.
http://www.gamespot.com/ps2/action/musouorochi/

GameFAQs
FAQs, cheats, saved game files, reviews, images, and a message board.
http://www.gamefaqs.com/console/ps2/data/938105.html

1UP
Preview, by James Mielke: "Supporting up to two players, Warriors Orochi will fill the gaping hole in your gaming heart between now and the next iteration of the Dynasty Warriors series."
http://www.1up.com/do/previewPage?cId=3160422