If I took voluntary departure while in a removal proceding and on the N-400 there is a question that asks if I was ever ordered to be deported, how do I answer it?
I would answer yes and then provide a written explanation of the events and include all court/immigration documentation referencing the voluntary departure.  Since this was probably a long time ago, meaning that after that you had gotten your green card status back since you are contemplating applying for N-400, chances are that this is just for information purposes and will not impact on your ability to naturalize.