Pick up the RCA cable and plug the black and white jacks into the black and white inputs in the back of your tape deck.
Insert the mini-jack on the other end of your RCA cable into the line-in on the back of your computer, or the head phone socket if you are using a laptop.
Open your music recording software, such as Cubase, Fruity Loops or even GarageBand. Set the program up to record a new track.
Insert the audio tape you wish to digitize into your cassette player and press Play. Adjust the tape deck volume, and the volume on your recording program, so that the recording level---indicated by the level gauge on your program---does not exceed the maximum volume.
Rewind your audio tape back to the start once the recording level is set. Press the "Record" tab on your music recording program and press Play on the cassette deck. Save the recorded audio tape file to your computer's desktop.
Open your music sharing program by clicking on its icon. Drag the audio tape file from your desktop into your music sharing program; your audio tape is now digitized and ready to be imported to an MP3 player, burned to a CD or simply played on your computer.