PulseAudio (homepage) is the sound server used by Openmoko to mix output from several applications as needed.
neod uses PulseAudio to play the samples "startup" and "touchscreen".
The samples are loaded from files and can be changed or disabled at the configuration file /etc/pulse/session.
Turning the Neo1973 into a USB sound card
The sound server can easily be made available (and discoverable, thanks to Avahi) in the local network, effectively turning the Neo1973 into an overqualified USB sound card (see also: http://www.pulseaudio.org/wiki/PerfectSetup):
ipkg install pulseaudio-module-zeroconf-publish pulseaudio-module-native-protocol-tcp echo "load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1;192.168.0.0/16" >> /etc/pulse/session echo "load-module module-zeroconf-publish" >> /etc/pulse/session /etc/init.d/pulseaudio restart
Now on a Desktop with PulseAudio properly set up, the padevchooser applet lists the Neo's hostname as audio sink as soon as it is connected via USB.