I did this once using SimpleSound in OS9 on a PowerMac G4. Just connected the output of the tape recorder to the line input on the Macintosh and set all the levels correctly, and recorded it. Then i just saved it and copied each file into Toast and recorded a CD.

Was quite a lot of hassle though, and that was only for one tape, so it is not something I will do again. I will be leaving my tapes as they are.

There are probably better methods.