I have this recharging kit:
http://www.amazon.co.uk/Venom-Twin-R.../dp/B002HWRJA8
Its handy because it only requires one USB port to charge both packs, and the one you don't have on the back of the controller can be recharged by itself, without the console being switched on (has to be on at mains though).
And I actually paid £7 for the pack at my local ASDA.
Hope this helps and enjoy your gaming
