So in the dreck of all the iPhone apps that are littering the itunes store I have found a couple of photography apps that are well worth keeping.
Darkroom - Free or 0.99 for premium features.
This app does one thing and it does it well. It acts as a steadycam for the iPhone camera. In short it takes sharper pictures in darker conditions than the iPhone camera. The results really put the iPhone camera to shame and this is now my default picture taking application.
Camera Bag - $2.99
Applies creative filters to your images. Theses range from the classic polaroid to the over-saturated Lomo like. Take a crappy iphone picture open this up and hey presto something interesting can come from it.I like the Helga, Lolo and Cinema modes. It can be a touch slow but it does a great job spicing up your images.