it depends on your carrier and your phone. if you dont have a data plan thatn it will cost you $.03 a kb. Most carriers have some sort of place on their website where you can browse apps and click a button on them that send that info to your phone so it can download it. If your phone has windows...
there is no difference apple just wants to feel special and call their product something other than what it really is to try to make people fell like its a one of a kind item when its not and no there is no monthly fee for the DVR but the on demand depends on your provider