We try to make only enough bread to eat on the same day, but if you have leftovers, the best way to store homemade bread is unwrapped and cut-side down on a non-porous surface like a plate, at room temperature (not in the refrigerator). This preserves the crust a little more than if you put it into a plastic bag, which softens the crust very quickly. The exception is pita bread, which is soft-crusted in the first place and is great in a plastic bag–but wait till it cools before bagging.
How long can you store bread this way? Maybe 24 hours. You can extend that a little if you put it in a plastic bag (refrigeration optional), and it’s often OK for toasting a day or two later.
More in The New Artisan Bread in Five Minutes a Day, and our other books.