I am experimenting with this RFID Reader to help determine positioning while the Create roams around.  This is the Source Code for the PIC which talks to the RFID Reader to read the currently visible Tag (continuously) and makes the results available via the i2c bus.  The schematic above shows the pin connections.  So far this reader has worked Excellent at reading everything it passes while wall-following. 

Command Module Source

PIC 16F690 C Source

Video of Wall Follower with RFID for Location Sensing