Yes! You can donate online! You can do this entire pool without touching a piece of paper.
Clicking on this button will take you through the process of paying five dolla. It will actually charge you $5.46, since Paypal siphons off a percentage. Think about it, though - a postage stamp costs 42 cents. So you'd only save 4 cents by mailing it in, and an envelope probably costs more than that, anyway.
Or, email for other options.