I asked the director of a commercial i was shooting about a week ago about the "mm" size and he said it had to do with the size of the film...35/32/36 (somewhere around there?) is what they use for feature films.
Thanks for the info...and my budget isnt that big...my dad gave me an old 8mm (deff. not digital) camera to use for now. Its pretty cool to play around with...im trying to shoot a short for the summer competition...i hope it will be done in time. Thanks again!

One last thing, how do you transfere analog film to digital. This is important because i have to edit on my PC and i am shooting w/ an analog camera. Thanks