SoundCloud is going to be the next big thing after the popularity of Twitter dies down, I swear.
Also some anime/game-related remixes I've found and love.
Yoshino Yoshikawa - Mami-san's theme remix
http://soundcloud.com/yosshibox/mami-san
mnmtpnk - Kimi no Shiranai Monogatari dnb rmx
http://soundcloud.com/mnmtpnk/d-b-remix
DJ Mashiro - Icha Icha Princess Mashiro ecchicore remix
http://soundcloud.com/deejay-mashiro/icha-icha-princess
Submerse - Madoka Magica
http://soundcloud.com/maltine-record/submerse-madoka-magica
(Grab it here, it's Maltine Record's 91st release! http://maltinerecords.cs8.biz/91.html)
DJ DAI - Yayoi is Mind Kill