dude, the n75 is not out yet. dont buy 1 from those ebay dealers, those are scams.

MediaNet & Cingular Video aren't programs, so they're not something that you can download. You have to get the phone configured with the correct networks settings to be able to use them. Since there isn't a phone even close to the N75 carried by Cingular (at least right now), than there's not going to be anyway to configure it properly. However, the N75 is aimed squarely at Cingular, in terms of features, so I'd just wait to get one from Cingular. It's unlikely to be available unlocked much before Cingular has it anyway.