i doubt a ps3 will register a network through the usb port so usb tethering is out of the question.
that leaves one option. wifi.
android phones can be set as a wifi hotspot for other devices to connect to it. this solves the issue of broadcasting the signal. now to receive it... i do not think a ps3 has the capability to connect directly to wifi so you will need one of those wifi receivers used with computers with a cat5e connection on the back wired up to your ps3. once you configure the address, password, network type, etcetera you should be able to use your phone as an internet source.