Most say you shouldn't freeze pack film as the liquid can break out. It can be refrigerated at least.
Personally I don't even bother doing that. Heck, people are still buying outdated Polaroid film on eBay.
I think the expiry dates are very conservative.
Data sheet says under 10C for long term storage: http://www.canemco.com/catalog/Techn..._datasheet.pdf