It's Here! Chris Odom's Physical Computing & Robotics with the Arduino IDE - Volume One

ENC28J60 Ethernet LAN Network Module

$3.50

These things are a blast! Setting up a tiny server is surprisingly easy to do. I have some code and instructional videos here:
Code and Video Instruction set 1.
Code and Video Instruction set 2

Main Chip ENC28J60-I/SO.
The board 25MHZ crystal.
The network interface board HR911105A.
3.3 V and 5V power
Size: 58*34*17 mm