RFID (radio-frequency identification) is the wireless non-contact use of radio-frequency electromagnetic fields, for the purposes of identifying and tracking tags attached to objects. This is the ID-3LA, a very simple to use RFID reader module from ID Innovations. The only holdups are the 2mm pin spacing and you will need an external antenna. Power the module, hold up a 125kHz card, and get a serial string output containing the unique ID of the card.
Note: The new ID-3LA is essentially the same as the ID-2, but has a lower voltage input.