http://www.usa2me.com/site/default.aspx offers this good service .
i found it in faq on their site
question : Some merchants require a credit card with a US billing address. I don’t have one, what can I do?
answer : Use our Personal Shopper services. Send us the information on what to buy and where. We will buy it for you and charge your credit card for the cost of the item plus a nominal service fee.