This drive is a port of Bauland's nice work for TinyClrLib.
Added basic ability to write on Mifare1k and MifareUltraLight cards.
For further information about RFID 13.5MHZ cards;
I recommend taking a look at Miguel Balboa's amazing drive for Arduino.
Source Code: Here
Note:
Tests with MifareUltraLight cards are still to be done up to this time.