Hammer How to Enc28j60
First you have to get an Enc28j60, the following links may be usefull:
Next we will be soldering it on to the Hammer_Carrier
Also make sure that your 5V main power supply can supply the Hammer as well as the ENC28J60-H.
Software driver info:
The Good Kernel SPI API The Bad & The Ugly The current "driver"