I can't recommend anyone in particular, but the one they have on ThinkGeek was good (might only be a reader tho')
That would be: http://www.thinkgeek.com/geektoys/science/907a/Ahh the Phidget USB RFID Reader, that was the first one I stumbled upon (not on ThinkGeek though); yup, only a reader - I took a peek at the example code, quite simple :)
just don't expect to be able to use it with Blitz. :o>
Not out of the box, but it does come with a VC++ library (the one I mentioned in my first post), which to my knowledge can be glued to BlitzMax ;)