In fact I’d never heard of Open Sound Control either, but apparently it’s intended as something akin to clunky old MIDI, but over TCP. Flosc is a little Java server that sits and intercepts OSC packets and turns them into Flash XML packets. The classes in the zip below will allow you to connect easily to the Flosc sever and send and receive events and data to any connected OSC device.
I was using these classes for two way communication between Flash and Glove Pie (and thus the Wiimote) and it all worked fine. In theory you should be able to control any OSC device, including some pretty cool sound kit such as MaxMSP or Traktor.