Insert the black and white RCA cable into the line-out in the back of your tape deck. Plug the mini-jack end into the line-in in the back of your computer, or the headphone socket if your are using a laptop.
Click on the symbol for your music recording program, such as GarageBand, FL Studio, Cubase (see Resources) or any other program with recording capabilities. Set the program to record a new track; each program will differ slightly in this process.
Insert a cassette tape into your tape deck. Press "Play" on your tape deck and ensure the "Line-In" option is selected on your music recording software. Adjust the volume so the recording level does not exceed the maximum, as indicated on the software's recording level gauge.
Press "Stop" then rewind the cassette back to the start once the levels are set. Click the "Record" tab on your music software. Press "Play" on your cassette deck. Save the recorded music to your computer's desktop.
Open your disc burning program--such as iTunes, Windows Media Player or any other software with disc burning capabilities--by clicking on its symbol. Go to the "Preferences" or "Options" menu in your disc burning program. Find the "Import Settings" tab, which is usually in the "General" section of Preferences, and click on it. Select "MP3 Encoder" from the list next to "Import Using:" and click "OK."
Import the cassette tape file into your program by dragging it into the program. Go to "File" then "New Playlist." Create and type a name for your playlist, then drag and drop the music file into it.