Noted for future reference: how to use a Parallax RFID reader and Arduino to control a servo motor:
This is an RFID authentication system. It allows a person to place an RFID tag within
proximity of the reader device (usually 5-6 inches with this reader) and it will look up the tag
in an SQLite database to check if it should grant access. If authorization is granted, the
hardware device will turn a servo motor into a second position. The primary application of this
being the unlocking of a door. […] This project is very easily modified to do any sort of task.