Forum Moderators: buckworks
Greyeye
Here is a link for research purposes. There are multiple places to look from here [dmoz.org...]
I will say that if you are going to go with Authorize.net (which I personally recommend from experience developing back end APIs for it and based on my client's experiences with it) then be sure to find a reseller to do it with. You save $50 off of the set up fee that way. ($150 through a reseller vs $200 direct from Authorize.net).