If you're like me (and it's a tough break for both of us if that's the case) then you bought a bread maker because A. you enjoy fresh bread, yet B. you're either too busy or too lazy (guess which one I am) to make it the old-fashioned (i.e. hard) way. Now I know what you're thinking; you're thinking "boy, the previous sentence has way too many parenthesis in it". You're right, of course, but you're missing the point. Bread makers are meant to be convenient, so imagine my consternation (it's only fair; I'm imagining yours) when I went to make some hot, fresh sourdough bread only to find that I have to make something called a "Sourdough Starter" first!
Well as it turns out, even though making a sourdough starter is a multi-step process, and does require a little of my two nemeses, care and though, it isn't as big a pain in the neck as I assumed. So if you're unfamiliar with making sourdough starters here's how it works.
A sourdough starter is really just flour and milk or water, with an optional portion of yeast, depending on the recipe. These are allowed to sit at room temperature for a few days in order to catch live yeast bacteria. It sounds a little unpleasant, but most of us eat things that had feet and faces at one point, so a few bacteria really aren't anything to go all girly over. An any case this inhabitation is what eventually provides sourdough bread with it's distinctive taste. If you guessed that taste was "sour", well, you're right, but you really shouldn't have to guess about things like that.
Here's a good all-purpose sourdough starter recipe:

• Mix the following ingredients in a medium to large glass or plastic bowl with an electric mixer on its lowest setting.

• 2 cup lukewarm milk
• 2 cup bread flour
• 2 1/2 tsp yeast (one package)

• Cover the starter and place it a warm, draft-free spot for 4 to 7 days, carefully stirring it once every day.

• If the mixture bubbles and/or overflows the bowl then it's a healthy starter; the excess from an overflowing bowl can be discarded.

• If the starter ever changes color then it's gone bad and should be thrown away

• After allowing the starter to sit for 4 to 7 days it's ready to be used.

You probably won't need the entire starter all at once, but that's okay. You can remove however much is called for then keep the rest in the 'fridge. But this is where it gets a little tricky. You must always replace the portion of starter you used with and equal portion of water/milk and flour. You take 1 cup of starter, you mix one cup of milk/water and 1 cup of flour back in. It's a good idea to alternate between milk and water every other time, and to use the same kind of flour as when you first made the starter. As a matter of fact, even if you don't use the starter you must remove a cup or so of it and mix in new ingredients every week. Failing to do so results in a big lump of rancid goop, which is fun at parties but useless for baking.
The longer you keep the starter the sourer you breads will turn out. This is good for a while, but you'll eventually hit your sour limit. When the first bite makes your soft pallet crumple like tinfoil, it's probably time to make a new starter.
Bon appetite!