I know things like digital cameras etc have all sorts of odd USB adapters, but is the socket on a PS3 controller a standard type of USB socket that i can get 3rd party cables for?
I want to buy a USB cable from my local computer shop rather than getting an "official" cable if possible, but I don't know what that socket is called so I don't know what to ask for.
It's called "mini USB". You can get a cable that's normal USB to "mini USB" to charge your controller or whatever peripheral uses the standard mini USB connection. Good luck!