I have it in my wallet but have yet to use it. I just ordered it because I process so much through the 2CO interface for my 14 accounts, I figured it would be a means to emergency money should I ever need it. When I ordered it I was under the impression that it would deduct funds from the amount that was "to-be" deposited. Then when I received it, there was a letter that said something different and confusing so I never did anything with it.
I would be interested to hear what you know about it.
They aren't offering a UK one at the moment, at least I think that's the situation.
However, a few months ago CNET News.com had an interview with a PayPal executive revealing their continued expansion into the UK market this year. From that report it looked like they are planning on adding such services as the credit card. Very handy indeed, if it was to happen.