Unfortunately there is no flash on the iPhone's camera. The picture quality and the resulting video are really  good, but when it's dark you just do not see anything on photos. According to rumors, in fact, Apple is looking to buy from a specialized manufacturer a large amount of LED flash to be mounted close to the camera probably in the next version of iPhone.

These Items, according to a company in Amsterdam, are usually combined with 5 megapixel sensors. Hopefully we will soon see a new version of iPhone with 5-megapixel camera and LED flash.