FotoNivo on Haarlemerdijkstraat (not far from Central Station), or Kleurgamma (two shops). Kleurgamma do same day if you drop it in in the morning. Both have a good selection of 35mm and 120.Originally Posted by gr82bart
There are quite a few others too, but these are the two I use most.
Also, Retrophotographic in the UK are really good to deal with, excellent service and pretty quick delivery over to NL.