I weigh it after... after all, it loses moisture during the cooking process, and thereby loses weight. It'd be more accurate to weigh it when you're actually able to eat it.
I count my calories on Fitday - the PC version - and they have calories for both cooked and raw, so if I remember to weigh before I use the raw count, if not I use the cooked count. I think it would depend on what plan you're on and whether your source for calorie counting (if you calorie count) is for raw or cooked. Does that make sense?
I use fitday as well. When I weigh meat depends on how I'm serving it. For instance I make 1/4 pound hamburger patties so I use the "oz raw, yield after cooking" fitday option. If it is hamburger for tacos I use the "cups cooked" fitday option because I can't portion out my serving before it is cooked. I apply the same principle to any other meat.