The 1A usb charger included in the box with my HTC Desire phone works well. It looks exactly like this one:
http://www.htcdirect.co.uk/index.php...roducts_id=901. I used the original Sony cable.
It took less than 50 minutes to top it up from two bars. I haven't timed it exactly, I left the reader alone for this amount of time - it might have finished in 15 minutes for all I know.
Edit: I checked the part number, and my charger is identical to the one in the link. I can also confirm that the reader is usable while charging from it. Seems like a cheap substitute for the Sony charger, it also works with everything else I've tried it with. It is very slim and small, the build quality is excellent, I recommend it.