Arduino Mega 2560 Clone

"The Arduino Mega 2560  is a open-source physical computing microcontroller board based on the ATmega2560. It includes  54 digital input/output pins where  14 can be used as PWM outputs , 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header,. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP)The Mega is compatible with most shields designed for the Arduino Duemilanove or Diecimila.
The Mega 2560 R3 has an automatic reset software and  also adds SDA and SCL pins next to the AREF. In addition, there are two new pins placed near the RESET pin.. The Mega 2560 R3 works with all existing shields but can adapt to new shields which use these additional pins. The open-source IDE can be downloaded for free (currently for Mac OS X, Windows, and Linux).
"