Check out these photo editing images:
iPhone photo / image editing test
Image by Dean Terry
This is a composite iPhone photo and editing test.
The TOP image is the original iPhone image, and it is typically noisy (view full size to see noise level).
The MIDDLE was edited (levels, color balance) on the iPhone using Photogene iPhone app and still presents the same amount of noise.
The THIRD photo took the previous, Photogene altered image and, using Photoshop, ran a Reduce Noise filter with heavy settings, then doubled the image, blurred the top layer and set it to 'overlay mode' at 66% opacity. This is a pretty common method for making better, softer, smoky images. A much more rich, deep result.
iPhone image editing apps should consider adding noise reduction and automating some of the more common image enhancement tricks beyond just levels, even if they disguise it and call it something else.
See full rez : flickr.com/photos/therefore/3172156062/sizes/o/
Finally, one of the best ways to improve photos on the iPhone is to use an app that looks at the accelerometer to determine when you are moving the least. Try Steadycam. I use it instead of the built-in photo app.
Fantasmi e venti
Image by bia.hvid
Edited in Photoshop