Where: generally bedding areas and high-travel trails are good, and specifically fencelines (the theory is that the shock of jumping a fence will pop them off, I think).

When: obviously, whenever your deer lose their antlers. February and March are safe bets.

What do you do with them? Eh, they're just evidence that those bucks survived another hunting season. I suppose you could make a lamp or chandelier out of them, or if they're not particularly impressive, a nice set of rattling antlers. *shrug*