At this point it's all vaporware, unfortunately -- you'll obviously need something plugged into your television, whether that's an official Snapstick piece of hardware, or something like an Xbox 360 or an Apple TV that's designed to actually show that content off. But however they figure it out, the idea will be that you can use an iPhone app to program and then share web content on your television.
Interested? Doesn't seem to me like much more than a glorified web browser, but Snapstick's taking sign-ups for a private beta right now. We'll have to see how this pans out.