I recently started taking pics with my iPhone 4. In some pics, the sign is darker then I want it to be b/c of background sunlight etc....any apps or programs you use to touch up the photos? Just curious.
Doesn't the Camera Roll app have some rudimentary editing tools now?
Yes, if you're on iOS 6, you can tap Edit in the upper right corner when viewing a picture in the camera roll and get a couple of editing tools. The only one that would really do anything for you is the Enhance button–which may or may not help.
When you're taking pictures of an object with lights in the background, you're better off turning on the HDR setting before you take the picture. HDR tries to compensate for the lighting difference.
If you're not already, you should also tap on the object you're photographing before you take the picture so that the iPhone adjusts the exposure and focus settings for that object specifically.