How can you use PC speakers hooked up to a PC monitor that is being used as a screen for a PS3?

From what I can think of, there is no way due to the monitor not having a way to install drivers for the speakers. The only thing you could do would be to get a monitor with speakers built in and that uses an HDMI cable.

How are the speakers hooked up to the monitor ?
How are you going to use them ? ...for the PS3 ?
What kind of sound output is there on the PS3?
What kind of input is there on the speakers?

My dell monitor can pass the audio from the HDMI input to a standard 3.5mm audio jack at the back. You need to alter a setting in the monitor menu to make it work.