Need advise for online credit card processor

Although I have written several websites in the past (in php), I have never had to handle credit card transactions before. A close associate wants to move his existing business online, and we must accept credit cards. He has an Israeli merchant account. I have spent some time on google, but found lots of conflicting information as to the costs and fees and processes regarding accepting credit cards online. The partner would like to avoid paypal, as it seems to unprofessional for his tastes.

The site will be hosted on a Redhat machine, Apache, php, mysql,...

1) I know that I will need a secure server. Is there really any difference from where I get the certificate?

2) What tools do I have for communicating with the credit card processor. I understand that I must send and parse XML- are there any classes in php that make this easier?

3) Any other gotcha's?

Thank you.

there are programs created in php for this.. but note that you will also need the gateway to process your card... also to check the identity of the card... but.. i do say this much.. it will cost ya.. almost $200.00 to get this cc payment gateway... also.. tell your boss that there is nothing wrong with accepting paypal. Take a look here

Also.. for further notice... beware.. this program is a b!atch to install good luck