I don't have an iPhone, but I thought I'd pass this along for those who do. According to Zeldman, it works.
Sometimes your iPhone just decides to stop storing photos in your current roll. You take a photo, then you go to look at it and all you see is a blank square. Then you click on it and it just goes to home or something. A lot of people seem to get this problem.
Luckow Design Studios - Fix for iPhone Camera Bug
(via Zeldman's twitter)