Open Source OBD on a Mk3 golf

I've begun investigating Open source options for OBD on my Mk3 Golf. So far I have a spare ECU and connectors and have lashed it up to my laptop via an 'ebay' OBD USB lead. An initial test with VAG-COM (sharware version) confirms that the hardware is working, so now I am working on getting some software working to read / clear codes.

Heres a picture of my hardware: