TokyoTosho

Your bound to find what your looking for there (I got the Asian Kung Fu Generation PV's from them).

Also, if you use mIRC, here are two channels where you can find them.

Server: irc.rizon.net
Channel: #PV-Vision

Server: irc.rizon.net
Channel: #Kuraki-fans

#Kuraki-fans is where you can find subbed PV's. #PV-Vision releases good quality PV's but without the karaoke.