For indipendent developers a paypal account is a very relliable way to get payment IMHO. In fact when I preordered X2 and X3, from Egosoft, I paid with PayPal.
By the way. Is it possible to run Starfighter in a higher resolution than the standard Amiga? (I mean 1024x768 or even 1280x1024 native , like using RTG Cards, not scalers)