1156 are single filament for front corners and rear turns, 1157's are double filament for the brakes. (iirc)
I just did some light buying myself. Finally getting rid of the oem look and goin xenonish.. :P
http://motors.search.ebay.com/1156-bulb_W0QQfromZR40
http://motors.search.ebay.com/?from=...itle=1157+bulb