Open Sound Control (OSC) is a protocol for communication among computers, sound synthesizers, and other multimedia devices that is optimized for modern networking technology
I have used pyOSC with great success on OSX. The code isn't under much development but this is most likely due to it's stability and simplicity. I briefly tried txosc and it may warrant further testing.
My usage of pyosc is limited but it works well. eg.
import OSC
c = OSC.OSCClient()
c.connect(('127.0.0.1', 57120)) # connect to SuperCollider
oscmsg = OSC.OSCMessage()
oscmsg.setAddress("/startup")
oscmsg.append('HELLO')
c.send(oscmsg)