Cheese fondue can be made in advance. If it stiffens, simply heat slowly over medium heat. If it seprates, add a little milk. Chocolate fondue can also be made in advance and reheated.
I would also not add the wine or kirsch until you reheat it, if you are doing a cheese fondue. Reheat on stove or in a double boiler and stir, then put in fondue pot over sterno.