my guess is that you connect via hdmi with the ps3 and there is audio passthrough to your speakers via the output jack.
if you could get your pc sound on hdmi also then you could just leave the speakers plugged into the monitor.
another option would be to have a cable from the monitor and a cable from the pc connected to a splitter or switch connected to your speakers. generally i dont think this way is recommended as there could be problems
The monitor is shared between ps3 and pc. Here's some more info:
There are two small speakers, each one plugs into the subwoofer. From the sub there is a cord that goes to a volume knob on my desk. From that knob comes another cord which goes to my computer when I want to have audio from my computer. When I play ps3 I have to pull that cord out of my computer tower and plug it into my monitor.
I tried plugging the cord into the monitor and then playing around with the sound settings to get PC sound that way. No luck.
Any other suggestions would be greatly appreciated. I have posted in other forums and talked to friends and some guys at Future Shop. I also tried a splitter cable. Nothing has worked so far. I can't believe that there aren't thousands of people out there who also use one monitor for ps3 and pc and must have the same issue.
this is gonna be redundant.
if your speakers has an aux port, you could just get another 1/8 to 1/8 and leave your speakers plugged into your computer. then audio output from monitor to the speakers aux.