I cook pulled pork in the summer on the BBQ. You need to get a shoulder joint of pork and cook it in a low oven very very slowly (like gas mark two). The internal temprature needs to be about 200F for it to "pull" because that is the point at which the muscle breaks down and pulls apart.
This was a huge success with all of my flat mates, even the none slimmers! Next time, however, I'm going to double the sauce and poor over the pulled pork just before serving to make it less dry & even more delicious!