UBIQUITOUS NETWORK SOCIETIES: THE CASE OF RADIO FREQUENCY IDENTIFICATION is a "background papers" by by Lara Srivastava, Telecom Policy Analyst, International Telecommunication Union (ITU). It's actually a very accurate and comprehensive overview of the RFID R&D. The part about existing usage is of particular interest, few examples:

RFID to combat counterfeit drugs
Using RFID to manufacture dental prosthetics: The French company Dentalax has launched an RFID-based system for the manufacturing of crowns and bridges for the dental industry.
Vatican Library deploys RFID: About 30’000 books were tagged as of October 2004. It is likely that an additional two million pieces will be tagged.
RFID helps parents keep a tab on their kids: Parents can choose to rent RFID-enabled wristbands from the LEGO park administration for the purpose of keeping a check on their children’s whereabouts.
RFID tracks runners in marathons
Radio frequency tags in smart watches remind people that they may have forgotten something
...

A good complement of the other report about the "Internet of Things".