Something like this should work with the desktop part of android notify over wifi:

dbus-monitor --system "type='signal', interface='com.nokia.csd.Call', member='Coming'"
| sed -n 's_.*serial=\([0-9]*\).*_v2/n900/\1/RING/foo/foo_p' | nc -u 127.0.0.1 10600

dbus monitor outputs the dbus signals, sed turns it into something approximating the android notifier message format and then netcat sends it over udp to some host. Except piping data into netcat isn't working, which I am blaming on busybox.

Other problems: dbus monitor outputs stuff not in the watch expression at the start, profile output doesn't work with pipes, and netcat is not in extras

A python script is probably the best option, using the info on wiki.maemo.org/Documentation/Maemo_5_Developer_Guide/DBus/DBus_in_Freemantle