How to create unique download links?

Hello there people. I want to create or make a script which will work like this. Basically the problem I have right now is alot of Hotlinking and I have tried .htaccess files etc but they are useless to protect from l33chers. I want to make a script that when the person clicks on the download link it is a unique link that opens and will only be valid for about 10 seconds until the link will expire.

Some places that use these types of systems is http://www.filefront.com

Something like filefront would be excellent and that is the kind of thing I am looking for


If anybody knows of scripts like these made any help would be appreciated


Thanks alot