I am working in PHP on a Linux server with MySQL.
I have a requirement (that I have attempted to talk them out of) to collect credit card information from users so tha
First of, I am not a lawyer. I have implemented CC-handling code several times previously, but I am only familiar with Danish laws and regulations, so your mileage may vary.
As far as I know, there are restrictions in place (law and regulations from the CC providers) that you need to be aware of. I don't know where you are in the world, but in many countries you need to be PCI certified to handle credit card data and that is an extremely onerous, expensive and on-going process.
Other countries, or states, may have notification rules in play that requires you to pay the cost of notifying the card holder if security is broken - and unless you are very careful, it is not unlikely.
In general, I would recommend against that procedure. You may risk being liable for any costs if it goes wrong.