This is one interesting kickstarter project. Team called V1 Avionics is developing ARINC interface “box” which will allegedly enable connection and use of real parts and panels in flight simulators. This interface will handle data transfer between the flight simulator and the part or instrument using ARINC to comunicate.
V1 Avionics is a startup in the US in partnership with a team of avionics engineers in Spain. It is encouraging that building simulators is their passion. The funding goal for this project is $5500 and the pledge ends on January 18, 2013. Here you can find this kickstarter V1 Avionics ARINC429.
They also provided a link with a document that explains the basics of the ARINC 429 protocol.
* July 5, 2014. Unfortunately this project was closed down! They explained they have not been able to keep up with the expectations and planned schedule (they all have daily full-time jobs). Problem was migration from the prototype version to a production-ready version. Good new is that development of SIM429 interface will still be continued.