How do I create a mirror of my object?

The goal here is to be able to create symmetry between objects that attach to an AV. I can shift copy to make, well an obvious copy so my dimensions are identical but when it comes to rotating my copy using world and local pivot points, hopefully people will know when I say it gets frustrating. I spend more than half of my building time on getting one object to mirror its original.

Is there an easier way to go about this issue? Can I create a script that will rez a mirror of its object?

this is something we have wanted since beta. and still we don't have it it is very frustrating, especially to someone who likes making big wings with feathers.

Wow this is great thank you very much for the information