A little pricey? perhaps. A little extreme? maybe, but if you're going to shoot some video with the iphone, this would definitely improve your results. The Zgrip iPhone PRO by Zacuto, is an adjustable quick release handgrip system for shooting professional, stable video using the iPhone 3Gs. Check out the video below. The Zgrip iPhone PRO is available now for $295 , however a lower-cost consumer version is on it's way.
ZGrip iPhone from Steve Weiss, Zacuto USA on Vimeo.