Ethernet Shield - with SD holder and active level translators
New version with active voltage translators on the SD card and made a new graphical design, but it is 100% compatible with the 'old' one.
The Arduino Ethernet Shield allows an Arduino board to connect to the internet. It is based on the Wiznet W5100 ethernet chip providing a network (IP) stack capable of both TCP and UDP. The Arduino Ethernet Shield supports up to four simultaneous socket connections. Use the Ethernet library to write sketches which connect to the internet using the shield.
The ethernet shield connects to an Arduino board using long wire-wrap headers which extend through the shield. This keeps the pin layout intact and allows another shield to be stacked on top.
Updated: The updated version is now compatible with both Arduino Duemilanove & Mega boards, includes a Micro SD socket for storage, and has an on board reset controller (to avoid pesky startup errors)