I love the idea behind the photobooth's at weddings, but I dislike the price tag that comes along with them. Some rental units can cost an average of $1,000 and up! Why would I want to spend $1,000 on a photobooth alone?!
DO IT YOURSELF! It can save you hundreds! If this is something that sounds of interest to you, I dug up a couple of websites that might help you in your quest for a fun item at you wedding, that won't break the bank. Most of them have suggestions on which softwear to use, what kind of set up you'll need in terms of a camera (you can go polaroid or DSLR), ideas for props, etc.
Life With Leo - Do It Yourself Photobooth
DIY Photobooth Using MacBook & Ikea Curtains
Instructables - DIY Photobooth
Breeze Systems - DSLR Remote Softwear
The Wedding Lens - Photobooth at the Wedding Reception
The Things We Think But Do Not Say - How to Make a Photobooth