You can see a video walk through at PDF Pop-Up Pro
It's a software that allows the user to add pop-up boxes to pdf files that will display when opening and closing the pdf.
The coolest part is that we've been able to insert a newsletter opt-in form into the pop up boxes, which will allow your readers to sign up to your autoresponder directly inside of the PDF.
We need 10 beta testers to look over the software and locate any bugs that we haven't found.
We'll send you a complete working version with a temporary registration key.
If this sounds like something you can help with, and if you'd like to put a testimonial on the main page, please reply here with a working email address or send me a PM with it, so I can give you a registration key and a download link to the software.
(Windows only, sorry Mac)
Edited: All Beta Testers Will Get a Fully Functional Copy of the Software to Keep