arduino mega 2560 r3 keystroke interfacing

Hey guys i need some help.

I want use my mega 2560 r3 as a keystroke interface for a flightsim. All it has to do is send a key combination or a single keypress into my simulator. Could someone help me out or point me in the direction of how to do it.

I am a complete noob and new to arduino so be gentle ;).

My desktop is running on win7 64 bit

THX advance

An Arduino Leonardo or Arduino Micro board is able to act like a keyboard or mouse. http://arduino.cc/en/Main/arduinoBoardLeonardo

The Mega 2560 can't do that, it has the (virtual) serial port via the USB. If you want the Mega 2560 to connect to the flightsim, the flightsim has to read serial data.