Another option for getting audio into your computer is to buy a USB audio interface, like this (converts an analog signal to digital):
or just buy a USB microphone, like this:
Sources (you don't have to copy this part):
Griffin iMic audio interface: http://img.slate.com/media/1/123125/2069186/2111771/2123671/050801_gi_imic_hires_tn.jpg
USB Microphone: http://www.soundonsound.com/sos/oct06/images/podcast12samsonco1_l.jpg