I bought a plug-in, two outlet USB supply from E-Bay and some USB to mini B USB cables. I use the 2nd outlet for recharging my Ipod Touch. I also got a cigarette lighter plug-in USB supply from E-Bay. I think my total outlay was around $4 or $5 and they work great.
I have both an AC plug for the house and DC plug for my vehicle which accepts the USB cable. It is used to power the unit - I do not charge the batteries in the radio. That is done with a Powerex 9000 charger.
i have a few various batteries with usb outputs on them i have acquired over the years for my ipods and iphones and stuff. i find these very handy with the psr800. they can power the radio for a good bit of time and also capable of topping off the charge in the internal radio batts.