"Yes, you can do this. Home stereos always have one thing, and that is a head phone jack so if you don't want to disturb other people in your home you can still listen to music."
Find the audio-out port on the back of your PC or side of your laptop (usually a green marker with a picture of headphones or sound waves), and plug in headphones or speakers. If you only have the white and red stereo cables, head over to a wal-mart and buy a "Y-Splitter" so that it will fit into the computer and plug your stereo cables into the splitter.
where you plug in speakers/headphones
When you plug the headphones in, that disconnects the speakers, and no sound will come from them. Unplug the headphones to hear the speakers.
in the red or white at the back of the speakers
You plug in your headphones and turn up their volume as well as your speakers volume.
Check your settings.
You need more than just speakers. A Stereo System's Aux input might work to jury rig something that you can plug the Audio output from the PS3 and play the sound through your stereo. You could also try a Home theater system. A Sony PS3 stereo headphones set will allow you to hear the sound and also has a mic
Many amplifiers automatically disconnect the speakers when a headphone plug is inserted, unplug the headphones and the speakers should come back on.
It depends on the speakers. Bose computer speakers are not designed to connect directly to speaker inputs on your receiver, as they have their own amplifier. All Bose home stereo speakers can be connected.
That depends on whether or not your computer has speakers. If it does, then unplug your headphones, plug in the speakers, and make sure your volume is turned up. If you don't have speakers, then there is no way to do have sound without headphones other than to buy speakers. Most desktops have speakers built in to them, though.
Plug headphones in.
Nope - if your sound is coming from both the headphones and the built-in speakers, it's your headphone socket in the laptop - not the plug that's at fault ! Basically an audio socket is a switch. While no external speakers (ie headphones) are connected, its internal components direct the sound to the computer's built-in speakers. Inserting a plug into the socket breaks the connection to the internal speaker circuitry, and directs the sound to the headphones.