I've designed, for A-level, an iPod dock but i need some help with the electronics. I have a small amplifier circuit (from my GCSE electronics course) connected to a speaker which is at the moment powered by a standard 9V battery. I was wondering if anyone knows how to replace it with a rechargeable battery pack. I understand I will need a plug with transformer and a rechargeable battery pack and internal/integrated charger but am not sure where to get the components from and how to arrange them. Any help really appreciated.