Just recently I discovered a ingenious post by Abel Domingues about how to create AU Plug-ins from your SuperCollider code, which then can be loaded as plug-in in the audio workstation of your choice (Logic9, Ableton, Cubase…). I was able to build and use AU plug-ins in Logic9 & Ableton Live using SuperCollider 3.5.1 on Lion 10.7.4. It is important to use the correct version of SuperCollider here, since recent updates seem to break things (with SC 3.5.5. I was able to build the plug-ins, load them in my DAW but no sound effect could be heard).
However, here is the link to Abel Domingues fantastic post:
http://www.mojolama.com/building-audio-units-supercolliderau-big-picture