According to Wikipedia, accepting online credit card payments is possible in Italy
http://en.wikipedia.org/wiki/Debit_card#Italy. Anyone have experience implementing such a solution? Who has a good, low-cost solution with a good API?
I realise other options are Amazon FPS, Google Checkout and perhaps VISA International (and I would love to hear your feedback on those), but we are really looking for a low-overhead, "familiar" and local solution.
Take a look at PlanetAuthorize. They offer an API and have a module for vtigerCRM (I learned about them through vtiger). I haven't tried them yet, but it's another option for you.
If you are finding it difficult to implement a merchant account in Italy I would re-think what you are trying to do. Mobile payments are exploding in Italy and aligning with this market behavior could be an alternative strategy to consider.
We're based in Italy, and we accept payments via PayPal with no problems. If you want to handle payments directly via credit/debit cards, the most used service is provided by Banca Sella, which was the fist bank in Italy to support online payments, so it's very well-known. I'm not sure how/if they accept foreign customers however, nor have we ever needed their services, so I have no idea about their rates.
My personal opinion is that PayPal is the most trusted payment solution, but that really depends on your audience.