My wife recently was deep cleaning and ran across a few tape cassettes that she remembered she really liked and asked if I could convert or digitize the tapes to MP3s for use in iTunes and on her iPhone. I figured it wasn't a big deal so I told her I could before I thought through the process (that's fairly typical for me). In any case, converting tapes to MP3s using a Mac ended up being simple enough. After the jump, you can read my step-by-step how-to on converting cassette tapes to MP3 on a Mac.
The first, and perhaps the hardest step is to setup the physical connections actually connecting a tape player to the Mac.
You'll need any tape player with a headphone jack out and an 1/8″ stereo to 1/8″ stereo cable. You just need to plug one end of the 1/8″ stereo cable into the headphone jack of the tape player and the other end of the 1/8″ stereo jack to the Audio In port on the iMac.
In my case, I wanted to monitor through a pair of headphones and not through the iMac speakers so I plugged a headphone splitter into the tape player where one side was plugged into the iMac's In Line jack and the other into the headphones.