I happened across a Speckled Wood butterfly on our apple tree, that apparently didn't mind me shoving an iPhone about two inches from its delicate self. It was well into a sunny day so I didn't expect it to be so docile.
It also made for an interesting test of iPhone macro camera capability. The results in this picture are fair, though it has smeared the subtle feathery detail in the wing quite badly. I suppose that's to be expected from such a tiny sensor, with lots of anti-noise processing to compensate. The biggest difficulty I found was getting it to reliably focus on the point I was interested in, resulting in lots of shots of an in-focus leaf and a blurry butterfly. Theoretically you can tap the screen to indicate the point for focussing and metering, but I didn't find that to work particularly well. Worst of all it doesn't give any obvious positive or negative feedback on whether it thinks it has successfully locked on or not. I'd like it to flash a green square when it's got a good AF lock, and maybe a red disintegrating one if it has failed.
Note that this is a crop from the original. Click for higher res. Another major annoyance of the iPhone's Camera app is that when viewing the photos, it shows a low-res blurry version when zoomed in, leading you to think that the camera is significantly worse than it is, and making is very difficult to check focus. I really can't understand why they'd do this!