Credit Card Gateway

Hi, I need to implement automatic credit card processing in my PHP Shopping Cart script, using iBill Gateway service. The gateway works by sending a HTTPS POST request to a script on iBill server. The answer to the request is the result of the transaction (approved/declined,code,blah,blah,blah) in a comma seperated parsable string. I'm not sure how I can do it... Here's 2 ways I see it, not sure if it can work: PHP Collects Credit Card info + calculates order total ---> Send a POST request to iBill ---> Parse results --> Prints Approved or Declined message to client. In order to do this, I would need some sort of HTTP function in PHP and I'm not sure if there are... The other way would be : PHP Collects Credit Card info --> Run another program ( exec() ) that can do HTTPS POST requests and pass the necessary info to it --> Have this program output the answer from iBill --> Get this answer in the return value of the exec() function of PHP --> Parse the answer My problem with this solutions is that I don't know which programs can do this (I'm under a UNIX based system). Any help appreciated! Cedric