Our favourite iOS camera app Camera+ once enjoyed a lengthy exile from the iTunes App Store for repurposing the iPhone's hardware volume buttons as a camera shutter button. This was a great feature, and if you'd like to be able to snap some pictures using the volume button you still can with your jailbroken iDevice and SnatpTap.
Why would you want to use your volume buttons as a camera shutter? Using the hardware volume buttons result in a lot less camera shake in comparison to tapping on your screen to take a photo. The volume buttons can also be positioned to be in the same place you'd generally find a camera's shutter button (the top right). It just makes your phone feel a lot more like an actual camera.
SnapTap is also very easy to set up. Beyond purchasing and installing it, there's not much else you need to do other than open up your iDevice's built-in camera app and press one of the volume buttons to snap a picture. If you want to turn SnapTap on or off (or just the shutter sound effect), you can access its settings in your Settings app. That's all there is to it.
SnapTap ($US3) [ModMyI]