I think you can buy a US gift card[1] and use that instead. I haven't tried it, so don't quote me on it ;)

[1] - https://www311.americanexpress.com/BOLWeb/bolfeOrder.do?requ...

You could try purchasing a prepaid Visa, Mastercard, or American Express gift card online and have it shipped to you. I see that amazon.com has various prepaid gift cards. Another option I'd be less excited about is a "reloadable" (i.e. Green Dot) debit card. I believe most US issued reloadable cards require a social security number however.

Are you willing to wait "6 to 8 weeks?"

http://www.theverge.com/2012/8/21/3257144/bitinstant-bitcoin...

I was successful with a prepaid credit card with US dollar as the currency. Just go to entropay.com, create a credit card and put some money on it.