Mpd is supplied as a
http://www.freebsd.org/ports, under the name net/mpd5.
Therefore, the simplest way to get mpd onto your machine
is to install the mpd package or port.
For information on how to do this, see the
http://www.freebsd.org/ports.
Mpd can also be compiled and installed manually. This is useful for example if you want to change the set of device types supported by mpd.