Or on a laptop use the built-in microphone & use Audacity to capture/edit the audio as MP3s.

http://audacity.sourceforge.net/

For others with cassette tapes I just archived tons of answering machine tapes with one of these & Audacity to cut & paste only the messages I wanted to save. It was pretty easy because on the visual display the end of message beeps would stand out like a sore thumb

http://www.amazon.com/gp/product/B005OIB76O