Diario

I can't figure out who produced the song 'california'. Some people say it was weezer and that it's on one of their b-sides. Others say the rentals (an American rock and roll band fronted by Matt Sharp, former bass player for Weezer).

My guess is the rentals, however most people seem to credit weezer. As can be seen by comparing the last.fm listeners:
http://www.last.fm/music/Weezer/_/California
http://www.last.fm/music/The+Rentals/_/California

update: http://www.weezer.com/contact/