The new Arduino Mega is available

The Arduino Mega is a new version of Arduino with more IO capabilities. Its has 54 digital input/output pins, from which 14 can be used as PWM outputs. There are 16 analog inputs and 4 UARTs available as well.

The Mega is compatible with most shields designed for the Arduino Duemilanove or Diecimila.

The microcontroller is a ATmega1280 running at 16 MHz. For the rest, it has the same user experience as the normal arduino, but you need to download a new version of the arduino IDE.

Read more about the Arduino Mega: http://arduino.cc/en/Main/ArduinoBoardMega

Download the new software here: http://arduino.cc/en/Main/Software