Review: iPhone 4 Tripod Mount - SnapMount
tl;dr: Right in all the right ways, this is one of the two tripod mounts I keep in my bag.
There are finally a plethora of different iPhone 4 tripod mounting solutions on the market, and this is a very, very good thing. You can browse other Reviews on my website to find some examples of other great tripod mounts—some very nice for specific purposes, others that are only marginally better than duct-taping your iPhone to a tripod!