ebay digital downloads/ buy it now sales..

Hello The brief is simple, the solution. Well who knows? :-)) That's up to you! I sell digital products. I protect my PayPal sales from various websites by means of a PHP script allowing instant delivery on reciept of payment whilst hiding the download location to avoid digital theft. Now the problem, ebay "Buy It Now". I cannot get my head round how to give instant delivery of the digital product without sitting behind my pc when ever there is an auction in progress. I love my pc but not enough to take it to bed with me every night. I want to live that Internet dream, making money while i sleep :-)) At present i do not get to much of either - LOL OK so there you have it, i need to automatically give instant delivery of digital products sold on ebay. I need to protect the download location also. I need a realistic bid, a realistic time a scale. It has to run on Unix systems. I do not think it needs a more detailed study. Just gimme a price please! I will need an explaination of how it works as well. Mark.