Code:
void main()
{
CreateObject(OBJECT_TYPE_CREATURE, "creature_templateresref", Location(Vector(0.00,0.00,0.00), 0.0));
}
You'll have to do a Where Am I cheat to get the x,y,z coordinates, which go in the spots labelled 0.00 (in alphabetical order so x goes in the first 0.00, y goes in the second and z goes in the third).
:edit:
And you can attach that script to dialogue to spawn the NPC or you could put the NPC there through the module file (though I'm not sure how to do the latter).