In order to listen to your cell phone through your computer, you will need to establish communication between the two devices. This is easiest done with an audio cable that fits in your phone. Once you have the correct cable, you can listen to ringtones, phone conversations, stream the radio and more. Using your computer's sound card, you can even record audio from your phone onto your computer.
Go to your local electronics store and buy an audio cable that is compatible with your cell phone. Just bring your cell phone with you and the staff at the store will make sure you get the right thing. You need an audio cable that can connect your phone to your computer's sound card. Most cable jacks are 1/8-inch.
Connect your cell phone to your computer. Plug one side of the audio cable into your cell phone's headphone jack, and plug the other end into the computer's sound card jack. The sound card jack will have a small microphone symbol next to it.
Open up your audio software of choice. If you want to record the audio from your cell phone, you will need audio software that has recording capabilities. If you simply want to listen to your phone, you will be able to hear it through your computer speakers as soon as it is properly connected.