You can read the story of the writing of the song, too.

[To the melody of Sadi Moma:]

Join us now and share the software;
You'll be free, hackers, you'll be free.
x2

Hoarders may get piles of money,
That is true, hackers, that is true.
But they cannot help their neighbors;
That's not good, hackers, that's not good.

When we have enough free software
At our call, hackers, at our call,
We'll throw out those dirty licenses
Ever more, hackers, ever more.

Join us now and share the software;
You'll be free, hackers, you'll be free.
x2

The file free-software-song.au is a recording of Richard Stallman singing this song. It is also in Ogg Vorbis format.

This song is in a rhythm of 7/8; those unaccustomed to odd rhythms often take the unevenness to be a mistake. The meter can be analyzed as slow-quick-quick or 3-2-2.
Alternate versions

    * Another song, inspired by this one but mostly different, sung by the band Fenster (4.5M)
    * A rhythmic version of free software song in Ogg Vorbis and MP3 formats by Thor.
    * An improvised piano version by Markus Haist in Ogg Vorbis format (1.2 MB), released under GPLv3
    * Another rock-like version by Pjj & Hairyone in Ogg Vorbis format (1.6 MB)
    * A Spanish punk variant by ALEC in Ogg Vorbis format (1.4 MB)

You can get a typeset score of the song made with GNU LilyPond. LilyPond source for the typeset score is also available.
Disclaimer

The Free Software Foundation claims no copyrights on this song.
Sadi Moma

Here is a description of the tune of Sadi Moma, a Bulgarian dance tune, in an ad-hoc form of notation using letters for notes. A dash means the previous note continues. There are seven beats per measure, thus seven characters in each group.

D-CB-A- B-CBAG- G--A--B C--B-BD A--A--- D-CB---
D-CB-A- B-CBAG- G--A--B C--B-BD A--A--- A------


Here is the second voice. (This is not in the sound file.)

B-AG-D- G-GG-D- G--G--- G--G-G- D--D--- G------
B-AG-D- G-GG-D- G--G--- G--G-G- D--D--- E------


It is also available as an ABC-file.