It's a stand for your iPhone 4 (horizontal and vertical!) with a tripod mount to connect your iPhone to any tripod. Putting your phone on a real tripod instantly confers magical DSLR status. Take that, iPhoneography haters!
I haven't checked the actual web-site as I don't use Photoshop, but I love the effect and can see me using this myself. Where I pinned it from said "How to Create a "Double Exposure" in Photoshop — Daily Epiphanie"
Pico Flex Dolly offers that oh so smooth tracking camera shots that look just like the big Hollywood productions, but without any of the hassles and constraints of traditional camera tracking & dolly systems.