Antonio Banderas - Cancion del Mariachi

From the movie Desperado, here's the music video version of the tune used in the title credits (at least I think that's where it comes in! =)

You can also hear it on Desperado: The Soundtrack. It's also (allegedly) on MP3 - the price isn't listed, so I don't know if it's unavailable or free (yeah, chance of the latter? not so much! =)