After being removed from the App Store last year for including VolumeSnap (the ability to use the iPhone’s volume-up button to snap a picture), Camera+ has now returned the feature to their popular app (and this time, Apple approves).
At the time, the feature was considered an unauthorized hack, but Apple later added the feature to the native Camera app in iOS 5. I guess the moral of the story is that innovation is only acceptable if Apple does it first?
Camera+ for iPhone is currently on sale for $0.99 in the App Store ($0.99, link).