There is no browser/Mac combination that will allow you to upload video on snapfish (of course you have to pay ~$25/yr to upload video onto snapfish in the first place)
Just got a response from Snapfish on this same question and they indicated that they will have the ability to accept video uploads from a mac by late Jan 09.... since its mid '09 now they still have some time to make this statement correct.
I too was not able to upload my ipad videos to snapfish and was told it is not possible, however I did import my ipad/iPhone videos to my PC and then uploaded them to snapfisf from my computer and it worked!🙂