I got a PCB mounting 3xAA battery box from Maplins (order code CL18U, 39p each!). Instead of a PP3 battery clip connection on top, it has 2 metal pins sticking out of the back that are meant to solder onto a PCB. However, they are exactly the same distance apart that the charging points are on the bottom of a Bit. I just bent the end of the pins up, and sit the Bit on top of them to charge it up.
