Credit Card Payments

I was wondering what the easiest way to add credit card payments to an OpenCart site would be. The credit card details would have to be automatically processed and money sent to an account. If I sign up for the API and PayPal Worldpay, is it as simple as entering the API code, password and signiture? Would that allow customers to then view the option to proceed with a credit card when checking out? Is PayPal Worldpay API key etc what would be entered in the Direct Pay module? Also is the last option on the list 'WordPay' supposed to be 'WorldPay' and does it refer to the PayPal or RBS WorldPay?

Thanks for any help and please feel free to move this topic if it's not in the correct thread.

i want to know the answer too