Google Checkout is making some noise lately. It now covers UK merchants. One good feature of Google is that it simplifies your payment task. You don't have to enter your profile and information everytime you make a purchase using Google Checkout.
There are a million other ways to do this, though, including Roboform and a few others that are out there. They keep your payment info supposedly secure. I'm just not that trusting, and I'd rather take the extra minute or two and fill out my payment info rather than store it if there is even a slight chance of it falling into the wrong hands.
I agree there. Storing CC info on your server is not only risky, but pretty dumb(honestly) from a merchants point of view. Let someone else worry about the exposure that you get from something like that.