Hi All
I too am one of those unfortunate macbook users who got their headphone cable stuck inside the headphone jack. My macbook slid out of my hand as I lifted it up while it was connected to my stereo and the cable snapped off inside. I tried all the super glue tricks and super thin tweezers. Nothing worked. I was pretty devastated.
I even went to the Apple store and wasted 1 hour of my time waiting to get served (with an appointment) only to be told that the Genius guys would need the macbook for 3-5 days to have a look if they could fix it, but that more than likely the logic board would need to be replaced at a cost of $600-800. I laughed and said thanks but not thanks.
Don't waste your time or money on either of the above.
What you need is an external mini USB audio interface that plugs into your USB and your sound is automatically diverted through the interface. You can then plug in your headphones directly into the interface to hear sound, or you can plug in an audio cable from your stereo so that the sound can come out of your speakers.
THE SOLUTION
I got the BEHRINGER U-CONTROL UCA202 for about $40. It took me a while to find a place that sold it, but I eventually found it in a music shop. It's a small unit and a small price to pay for being able to play music out of your macbook or laptop again.
This is what it looks like: http://www.musiciansfriend.com/pro-audio/behringer-u-control-uca202-usb-audio-in terface
The downside is that you are always carrying out the small interface with you... but I'm ok with that.
Good luck and I hope this helps !