There are some really great open-source Python libraries for UHF RFID tags (battery-free tags that can be read from 6+ meters away): <a href="http://www.ros.org/wiki/hrl_rfid" rel="nofollow">http://www.ros.org/wiki/hrl_rfid</a><p>These form the basis of my PhD work. Turns out you can do some cool stuff when you couple it to an autonomous, mobile, manipulating robot: <a href="http://www.hsi.gatech.edu/hrl/pdf/pervasive_computing_2010.pdf" rel="nofollow">http://www.hsi.gatech.edu/hrl/pdf/pervasive_computing_2010.p...</a> (PDF)