I decided to give making a sourdough starter a try, dug around, and found this page, among others. Most were pretty similar, so I started with their method. Which, be it noted, is slow this time of year; I tend to keep the thermostat down to save on the gas bill, so that makes for a slower process.
Short version: whole-wheat flour and water, mix, let sit a day. Take out half, add all-purpose unbleached flour and water to the remainder, mix, let sit. When it starts showing bubbles, repeat the feeding twice a day.
Mine's still going slow, and I'm cheap, so tried the suggestion that the starter not ready for making bread will work for biscuits and such, here's the result.
The starter is working, I fear it'll be a few days more before it'll be ready for a try with bread.
And, I just discovered, I could've looked at Brigid's place and gotten a faster starter going.
And, by the way, if you haven't seen her stuff yet, you really ought to remedy that. I'd suggest starting here, if you don't start with the above.