How can I simultaneously input and output audio for recording music on my macbook pro?

I have a 13 inch macbook pro 2.53 GHz with only one audio port. I want to be able to plug my microphone into the audio port but also be listening to headphones that will somehow be connected to the macbook. Any suggestions?

MacBook pro best answer:

Answer by s3ntin4l
Considering your macbook pro probably has a microphone jack and headphone jack. Plug your microphone into the microphone jack. The headphones into the headphone jack and set your audio settings to have live feedback from your mic. Have to look it up, as I am not familiar with the sound control panel or settings for Mac.