I've made quite a pile of gingerbread houses in the last few years, but a recurring problem is getting the icing as smooth as I could like it.
I'm not a baker or a cook of any kind - this is the only thing I do in the kitchen all year :P For the parts of the houses that I choose to put icing on, but not decorations my icing is always a little lumpy, and not as smooth looking as I would like.
I use the icing recipe from this site - 2 egg whites, 5 cups of icing sugar.
First, try sifting your icing sugar--depending on the brand they put some additives which can cause lumps. Sift before you measure the sugar. Also, you might try this recipe
