I have no idea what's going on with a PS3 but unless you know the current output on those USB ports is 500 mA USB 2.0 capable I wouldn't do it. An eGo charger requires a minimum of 420 mA current to operate. Even using it on a standard computer port isn't allowing a lot of room for error. If the PS3 ports can't put out 500 mA current you can kiss them goodbye connected to an eGo charger dongle.
Why not just pick up an AC to USB adapter on Amazon for about two bucks instead of risking the PS3?