Maybe something like this:
http://www.fye.com/Psp-Retractable-C...VVviewprod.htm
It will charge and sync from a computer, or a USB wall wart, since it connects through the mini-USB and the power port.
I picked up one from CompUSA with just the USB cable, and I have one of the small Apple iPod chargers. It is great for travel (the apple charger is good from 110-240V, if you're outside the US), plus I have cables to charge my PDA & iPod, so it definitely minimizes the carry-on weight.