I know you need a US business, so what exactly would I have to do to get this done? Get someone in the US to register it for me?

Have you contacted CCBill? Since CCBill is mainly for adult subscriptions, it would be best to confirm with them their requirements.

Yes, I need adult subscription.
They are only allow Visa I believe if you aren't a US citizen.

i wonder what if I set up a US business, and US bank account, but the person that signs up is from the US and has a US address?

When you say signs up is from the US and has a US address, do you mean your customer? CCBill will allow you to accept credit cards internationally, as long as it goes thru their scrubbing techniques.

You should call them to find out what they need - they will work with you. You can set up an EIN (http://www.irs.gov/businesses/small/article/0,,id=98350,00.html) online if that is what they require from you.

I mean me signing up for CCbill, I'm not sure, they either don't acccept canadians, or only accept Visa not MC. Someone in another post said I need a SSN or something?

CCBill US needs a US corp/business and a US bank account with a US director.
If your adult subscription niche is in the bondage or extreme in anyway they won't take you.

hope that helps :)

Depending on how "adult" the content of your site is, there are providers in Canada that can get you going. This would require fewer hoops for you to jump through and keep your money on Canadian soil where it would be nice and safe :)