I saw an old link to this site, but thought I'd re-institute it. I've just tried it very successfully.

Here's the site: https://secure.paypal.com/refer/pal=mschaefer%40onebox.com

It offers a $10 bonus to sign up (free money) and allows you to pay your friends money using your credit card.

If you're so inclined, you can email your buddy $5000 and have him cash it for you -- since the transaction is charged to your credit card as a purchase, you just earned 5000 miles on your credit card, plus you get a free $5000 cash advance.

Too good to be true in my book.