You can do this very easily.
On Mac OS X, MIDI-enabled apps should appear in the MIDI control panel, you can just send MIDI from Ableton to Resolume via the Ableton I/O controls.
On Windows, set up the MIDIOX MIDI Yoke drivers. Set Resolume to receive from a virtual MIDI port, and send MIDI from Ableton to that port.
I'm using IPMidi (http://www.nerds.de/en/ipmidi.html
) for this, it works fine. I can run Ableton and Resolume on the same machine, or on two machines, connected over WiFi.