Cell Phone-based RFID sensor

One of the functions that I think would be great to have is a cell phone-based RFID code reader or sensor. RFID tagging will become much more prevalent and its use will take different forms than todays....for example, RFID tagging of animals...sounds cruel but is much more reliable than tags.

But finally...maybe there are earlier examples that I haven't come upon of a cell phone based sensor: Read about its intended uses here.