PAYFLOPRO
If you use Verisign to process credit cards , you will want to make use of these functions. A function or two will process your request and you will get back a response . Once that response is compared to a set of known codes , you will know whether or not the transaction succeeded.
CYBERCASH
To make use of Cybercash you need to do a custom installation of PHP. The functions that comes with PHP are not as clean as those that work with PayfloPro . However, there is a nice library in /ext/cybercash of your PHP installation that should make credit card processing easier.