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.
I did Nigella's 24 hour slow roasted pork once for a crowd, although I could only get a 6kg shoulder which was just as well really because I don't think I would have got any bigger in the oven.
Ooo. I did it at the weekend. 1:5 kg pork shoulder in fan oven at 100c for about 6 hours and it fell apart. I stuck a beef casserole in too to save on fuel.
I have tried it on the slow cooker but for some reason do not enjoy it so much. On the other hand I do love a beef brisket in the slowcooker.
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!