Creating an Active Load while controlling the PWM

I'm working on a project where im creating an active load using the Arduino to basically act as a knob for the rest of the unit. I am new to Arduino and programming is not strong point. I don't understand how I would code the board to vary the input to begin with. Any help that can be given to this project would be greatly appreciated.

I don't understand how I would code the board to vary the input to begin with.

I haven't a clue how you would make the Arduino affect the INPUT, either. After all, the input is coming from outside the Arduino...

But, if it helps, I voted for option 2.

Perhaps this will get you started - http://arduino.cc/en/Tutorial/AnalogInput

I voted for 2 too.

I to voted for 2
Why is this a vote?

Are you wanting to make a load who's resistance is controlled from the arduino?
If so you need a smoothed PWM output signal applied to a FET to operate it in the linear mode.

I didn't mean for it to be a vote but yes i need to control it from the arduino and in the schematic coming out of the PWM I have it going into a FET. But depending on how many WATTS you want to give off and the input voltage won't that change PWM

Sorry that makes no sense at all. Can you explain what you are trying to do.