I’m not a SC user, but perhaps these links will help to steer you. Pdf of the author’s slide presentation:
http://opensoundcontrol.org/publication/use-open-sound-control-supercollider-server
and this from an ambitious user:
http://www.local-guru.net/blog/2009/03/08/osc-events-in-supercollider
I think there’s been OSC support in SC for a long while now, so I’m guessing some basic classes are part of the standard distribution OSCresponderNode looks like a class for dequeuing and perhaps also parsing OSC messages.
Cheers,
–Bob