Hi there! This Instructable shows you how to "download" any song you want to your computer, absolutely free.
From this Instructable, you'll be able to save to your hard drive your favorite music, expanding your music library.
Note: this system requires no outside reworking of your computer: no cables, no amps, nothing.
Step 1: How it Works
This system is the equivalent of plugging in a microphone and recording the music as it comes out of your speakers. However, this way, no quality is lost, because the audio being recorded has never actually left the sound card.
Legality: internal recording is legal under the DMCA, because it's essentially the equivalent of recording radio. (Note: I might be wrong, so don't sue me.)