Well heres a couple of things to know... The new PSP slim (i'm not sure about the Phat) uses USB On the GO which is a new crazy flavour of USB. There is now a 5th pin, also if you look at the USB whitepapers there are also resistors attached to the D+ and D- connectors depending on the type of device. If it were me I would do a little more research and probably end up de-soldering a 5 way dip switch off of an old motherboard.
-yngmike