create a membership script (which automatically expires after two days)

I want to deliver streaming Flash video on my Joomla! website. However, this will be restricted to people who have paid to view the video. I want to limit the number of days which they can view, the online video so I need someone to create a script so that once a purchase has been made, they will receive an e-mail with a username and password to access a particular page on my website. once they have logged in, a timer will commence, and will automatically cancels their membership ( or disallow them from logging in) after two days. Another option could be to limit the number of times they can visit the page until it expires. Either way, I'm open to your suggestions. Ideally, you will have had experience with shopping carts and delivery of online products. please send me any relevant links so I can see what type of work you have done before. There will be ongoing work, as I have 40 different products that will require this ability to be time limited. PAUL