I just published the version 1.0 of the DMX RDM library as an Arduino library with sample code.
Download the file from http://www.mathertel.de/Arduino/DMXSerial.aspx, unzip the file to your Sketches\libraries and try the example in libraries\DMXSerial2\examples\RDMSerialRecv.
The hardware requirements for that sample is a DMX line attached to the serial port, the data direction switch at pin 2 and some led to the ports 5, 6 and 9.
The schema of the DMX shield documented in http://www.mathertel.de/Arduino/DMXShield.aspx can be used as well.
Any feedback is welcome.