It would be EXTREMELY useful if anyone could point me to a place where I could find the PSPICE part for the Arduino Mega 2560, or at least a place that teaches one how to make this particular custom part within PSPICE/OrCAD. I have googled, but so far no dice.
Isn’t PSPICE a circuit emulator? I doubt you will find a PSPICE description of a microprocessor like the ATmega. You might be able to simulate the I/O drivers based on the information in the datasheet (they are pretty simple.)
As for OrCAD: http://lmgtfy.com/?q=OrCAD+create+part