What are the options to accept a credit card payment from an iPhone application? This will be a stand alone application, not an iPhone specific web site. Can I integrate with a payment gateway like Authorize.net? What about paypal or Google checkout? I know on some web sites, it will take you to a paypal site for the payment authorization - can this be done over http requests, instead of forcing the user to another website (which won't be available from the app)? Are there any security concerns with these payments from an iPhone as you can't install an SSL certificate?
I don't want to use the Apple micro-payments that will be available in the 3.0 release as there will be many small charges, and I don't want to give 30% to Apple each time.
Is this even possible, or will I need customers to create an account on my web site beforehand, pay with their credit card, and then have the iPhone interact with my database to get their available balance (the amount they charged through the web)?