Once more I have a handfull of links, which I haven’t summed up here. First of all I found a really nice tutorial by the Teaching Enhancement via Small-Scale Affordable Labs (TESSAL) Center, introducing into experiments with 13.56 MHz RFID. Their summery of the fundamental concepts is really helpfull in my opinion. Further they provide an short online test, proofing your basic knowledge on RFID, as well as all their materials on this class.

One more short introduction into the RFID basics by Priority 1 Design.

Another RFID introduction mainly from the EPCglobal perspective.

Further more the articles by Roy Want should not be missing.