Re: RFID
You should start off with a serial communication, example RS232.
It is easy to work with, and gives you maximum control.
Conversion to USB communication is easy in a later stage,
using RS232 to USB converter or IC level FT232 USB chip.
There are many other type USB chip in the market,
you may try searching for keyword "USB transceiver IC".
You may like to refer to the following website
for the suggestion mention above.
It contain circuit schematic interfaces with RS232 or USB,
using serial communication protocol.
**broken link removed**
Hope that these information helps.
Siong Boon