And what are you playing your tapes on? Any tape player with a headphone socket will work, but the better quality player you have the better the quality audio file you'll end up with.
Basically you need to connect your tape player/hi-fi amp to your Mac, fire up some software, then play the tape.
If you have a decent hi-fi setup and a spare pair of audio out ports you'll need a RCA to mini cable like this one from
Monster. You'll need an audio in port on your Mac, but if you haven't got one you'll also need something like the
Griffin iMic, which plugs into a USB port and gives you audio-in.
If you haven't got a hi-fi you can use a tape player with a headphone socket, but I can't imagine that the quality will be as good as from a hi-fi. For this you'll need a mini-to-mini cable like
this but longer. Plug one end into the headphone socket and the other end into your Mac/iMic.
As far as software goes I use
Sound Studio which came bundled with my Mac. (If you get an iMic Griffin offer
Final Vinyl. I've tried this but didn't have nuch success with it.) The software will allow you to play the entire tape, then split it out to individual AIFF tracks which can then be renamed and imported to iTunes. Once in iTunes you can convert them to whatever format you prefer then load them to your iPod.