What Doug said. I cook butts, pull the meat and freeze it in individual bags so I can bring it to work for samies. I throw a little apple juice in with the pork and man-o-man is it good.
I wrap in heavy duty foil and place in the oven at 300 for 30 minutes...if thawed. Slightly frozen still...about 350 for 35-45 minutes. Slow steam from the moisture revives any dryness.
The best way to reheat meat is in a closed environment. I prefer to vac seal and reheat that way. These days I use a finishing sauce for pulled pork. I use 3/4 cup chicken stock 2-3 TBS of butter along with 2-3 TBS of BBQ sauce. I use 2-3 TBs for these cause they are just eyeballed. This is a nice flavor packed sauce that adds moisture with out changing the taste of the pulled pork too much, just enhances it IMO. This amount is enough to moisten at least 1 Butt. I used to use Apple juice but found that changed the taste to much for me, JMO. Try it, I think you'll like this approach.
several great ideas guys..... thanks. Bryan's seems to fit in with my thought process the best so far. But I will try several of them, guess that means I need to get more butts on the fire!