I guess that depends on your cell phone. You can charge your 505 with any gizmo that charges the Sony PSP. Here is one:
http://www.igo.com/productresults.as...+COM6600654-01
You'd have to get other tips for your PDA and phone. The other strategy is to take a USB wall wart and USB based cables for your devices. Here is the cord for your 505:
http://store.itrimming.com/dsonpspdat01.html
This approach only works if your phone and PDA have USB-like ports for charging, or someone sells adapter cables.