The only restriction is that you can't be coming from an anonymizing proxy when you buy paid time (and that's the same worldwide) -- we haven't, knock wood, had the same kind of fraud from certain parts of the world that LJ used to suffer, so we haven't needed to put any regional restrictions in yet. (Fingers crossed that we won't need to.)

We take Visa, Mastercard, American Express, and Discover cards -- if you don't have a card, there's a list of online VISA gift card providers, or check with your bank. We'll also take check and money order in US dollars, or if all else fails, American Express travelers' checks.