After prying apart the plastic case and removing the only two screws you're pretty much free from the plastic casing. I wanted this battery pack to plug into the bottom of the iPhone so I removed the iPhone connector from the 5 female pin headers holding it in place. Then soldered in some wires to extend the iPhone connector to the top of the battery. I also folded the circuit board up onto the battery to save in size and to allow the led's (which show battery power) to face forward. When doing this, you're also repositioning the micro usb port, don't forget to leave access to this later when/if you "re-case" the battery.
The cosmetic's of these projects always seems to get away from me. If i had access to a plastic vacuum molder I am sure i could have made a much nicer final product, but this time i got cheap and chose to just wrap it in electrical tape. I also chose to use a piece of white plastic from a nightlight to allow the battery strength lights to shine through. Behind the white plastic is also a button once used to turn on and off the charge. Since the battery charges once plugged in, this button is kinda useless, but still accessible through the white plastic.
That's all folks!
Very simple mod which can bring some life back to your old iPhone battery case.