I'm working on a write-up about this project, I'll include links, code and schematics, but there are some other things that need my attention now..
There is a problem with the current version of the ethernet library, ports aren't closed properly so it runs out of available ports quickly.. Etracer came up with a good solution, see comment #16 of this thread.. His solution can be found here:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238640832/0#0
To get the RFID stuff up and running I used the code that Marc Boon posted last year: