The sound loop you are probably listening to right now (if your browser
is able to automagically play MP3) is my modest creation of a short
afro-cuban Rumba Guaguanco with the wonderful open source drum machine Hydrogen which is freely available
The source file for the loop you are listening to is available for
download right here: guaguanco.h2song.gz.
I consider this file as a very modest addition to freely shared musical
culture and therefore you can do whatever you please with it. To get a
proper sound representation with Hydrogen you need to download and load
the following drum kit: http://www.hydrogen-music.org/getfile.php?file=ErnysPercussion.h2drumkit
currently does not support non-*NIX operating systems, so Windows users
will still have to wait quite a bit for it to become available for them
too. If you can't wait, just switch to MacOS X or Linux in the meantime.