I played around with these a long time ago. Still have one and a bunch of film cartridges laying around.
As far is film goes, you have 3 basic choices (assuming you want b&w negative): 16mm movie film (it has been a while, so I don't know what is available), 35mm film slit to 16mm (then you need a splitter), or 16mm microfilm with somewhat specialized development). I suggest you check
www.subclub.org for information. Also try
http://www.subclub.org/sponsors/goathil2.htm for film.
Here's one approach to using Agfa Copex microfilm (at ISO 50) that worked reasonably well:
Agfa Copex rated at ISO 50 - though it was best to avoid high contrast subjects (I have no clue as to whether copex is still available):
Mix a Sodium Sulfite solution of 2 oz Sodium Sulfite to 1 liter of water
Mix 2.5mm of HC-110 (concentrate, not stock solution) to 200ml of Sodium Sulfite solution
Develop for 6 min at 68 degrees F with agitation every 30 seconds.