Couple of ways that I've reheated pulled pork ...
If you have a crock pot
Put the meat into a foil pouch, don't seal it up completely, and set it in the crock pot. Add about a 1/4 cup of water to the bottom of the crock pot to allow the meat to "steam" as it heats up. Will keep the meat moist and tender.
I've placed the amount of meat I'm wanting to heat up in a bowl and covered with a damp paper towel to produce the "steam" effect again.
Just a couple of suggestions, holler if either of those means aren't feasable and we'll get something out there to ya.