http://bit.ly/lj8EJM
to get npcs to spawn the house must have each room over 8 wide and 5 high roughly, chair, table light source. proper backing (not coloured bricks, they wont work anymore) and room must not share doors or it counts as 1 room.
also each npc has set criteria to fufill b4 they can spawn, like a merchant you need 50 silver, nurse u must increase ur max health
after the criteria has been fufilled it shouldnt be any more than a few minutes, if they dont spawn make sure you have the house built properly and completed the requirements, might be worth reloading the world, i know the demo guy can be a pain to spawn
