What methods (in programming/web dev terms) were used to take payments online before such things as Paypal, Google Checkout and various gateways and API's.
How were such transactions carried out?
CC Info was downloaded and then Processed locally (securely). Sometimes Manually, Sometimes Batch, via a dial up line (securely). This is often the case today as well.
Actually, not that much differently if you take all the middleware out of context.
Payment gateways typically provide a secure, offshore way to store CC data and provide advanced validation, invoicing etc.
But besides all that great funk behind the scenes, they're still saving it into a database and handing the information over to the bank.