I discovered a nice little trick for GNOME users running GStreamer apps. You can play sound across the net from any GST app, like so:
Open gstreamer-preferences, and set the sound output to the “Custom” option. Put in the text entry underneath esdsink host=1.2.3.4 where 1.2.3.4 is the IP address of where you want the sound to go.
On the destination host, make sure ESD is running with the options -public -tcp.