While reading Deuteronomy tonight, I found a passage which, in my opinion, could be reasonably extended to cover the ethical standing of Napster and the copying of mp3 files for personal use.

Deuteronomy 23:24-25 says:

    You may eat your fill of the grapes from another man's vineyard, but do not take any away in a container.
    It is the same with someone else's grain -- you may eat a few handfuls of it, but don't use a sickle.

    (The Living Bible)

In other words, it is permissible to consume the fruit of another's labor in situations where:

  1. The crop is not damaged, or if it is, the damage is extremely small in comparison with the overall harvest. (Record sales increased after Napster became popular.)
     
  2. You do so for personal use, and not to sell to others.

Nor are we commanded to download just a few tracks from an album. You may eat your fill, Moses said of G-d's commandments. Indeed, the Talmud says "We will be held accountable for neglecting to enjoy the legitimate pleasures G-d sends us."

You heard it here first, kids. G-d wants you to share MP3s.