Album Purchasing with Google Checkout & PayPal (existing site)

I require someone to program a php add-in to the website :? [[login to view URL]][1]? to allow for Google Checkout & Paypal users to be able to automatically purchase and download the album, the album must be downloaded in a secure/hidden format so that once a users purchases the music they aren't just given a directory with mp3's in it that they can pass onto all there friends/get posted on the web. currently the site is in PHP, not sure if that would even be required to code this stuff in though. Thanks Jeff Hunter