Ethernet W5100 R3 Ethernet & SD Shield

The Arduino Ethernet Shield R3 (assembled) allows an Arduino board to connect to the internet. It is based on the Wiznet W5100 ethernet chip (datasheet). The Wiznet W5100 provides a network (IP) stack capable of both TCP and UDP. It supports up to four simultaneous socket connections. Use the Ethernet library to write sketches which connect to the internet using the shield.
The new Ethernet shield now includes a micro SD card connector, it is MEGA compatible and an on-board reset controller.