I use a 3-2-1 method at 220 - 230F with a little apple and hickory wood on my Weber Smokey Mountain:
1.) Hit them with rub right before going on the smoker then cook for 3 hours
2.) pull and wrap with foil (adding apple juice, brown sugar, and bacon grease in the wrap), put back in the smoker and cook for 2 hours
3.) remove them from the foil, lightly coat with a good BBQ sauce (I make a homemade one), and put back in the smoker for 45 minutes to an hour.
Oh, and make sure you peel off the membranes on them before you put them in.