The Arduino Ethernet is a microcontroller board based on the Arduino Uno, and incorporating a WizNet W5100 TCP/IP Embedded Ethernet Controller. It can be programmed like an Uno via a six-pin FTDI -style serial connector. The Arduino USB 2 Serial adapter or any FTDI-style USB-to-serial connector can be used to program it.
A separate power-over-Ethernet (PoE) module is soldered to the board to provide power from a conventional twisted pair Category 5 Ethernet cable. It is IEEE802.3af compliant, and works with all compliant PoE injectors currently available.

Techinal Specifications
Microcontroller : ATmega328
Operating Voltage : 5V
Input Voltage (recommended) : 7-12V
Input Voltage (limits) : 6-20V
Digital I/O Pins : 14 (of which 4 provide PWM output)

Arduino Pins reserved
10 to 13 used for SPI
4 used for SD card
2 W5100 interrupt (when bridged)

Analog Input Pins : 6
DC Current per I/O Pin : 40 mA
DC Current for 3.3V Pin : 50 mA
Flash Memory : 32 KB (ATmega328) of which 0.5 KB used by bootloader
SRAM : 2 KB (ATmega328)
EEPROM : 1 KB (ATmega328)
Clock Speed : 16 MHz
W5100 TCP/IP Embedded Ethernet Controller
Power Over Ethernet ready Magnetic Jack
Micro SD card, with active voltage translators
For more information, please visit this products data sheet.