The FNBpay.com site isn't the banks site... it's the site for this particular service.. which I'm guessing is aimed at US based people. I really don't think it's a BookMaker site/program.. as the first poster found out about it through BetPhoenix -- or are the two sites somehow related?
The bank's site appears to be
http://www.fnb.com.mx/, which has English and Spanish. I've also gotten an email from Angelo from an fnb.com.mx address and, as far as emails go (which isn't very far), looks legit.. with 'legit' just meaning from the bank. I'm too lazy to check and see such a Mexican bank exists.
But... like I said, I've not sent in any paperwork. I'd love to hear people's reviews.