The "beginner" recipe at Sourdough.com looked really great, with a small problem: the recipe is written in metric and by weight. I don't have access to an accurate scale right now, and I'm stuck using volume measures.
I did some math and some trial and error and think I got a working conversion out of it. You'll want to check the original recipe for technique information, but here is the general gist of it:
Mix 1tsp yeast and 5 tbsp warm water. Let rest 10 min.
Add 1/3 cup water and 1/2 cup flour. Mix, cover, and let rest for 2 hours.
Add 1 3/4 cups water and stir until sponge dissolves.
Add 4 cups flour and mix just until shaggy. Cover and let rest 10min.
Oil hands and workspace, knead for 10 seconds.
Let dough rest, covered, in oiled bowl for 5-8 min.
Knead 10 seconds. Let rest 10 min.
Knead 10 sec. Let rest 30 minutes.
Knead 10 sec, let rest 45 min.
Form loaf, let rest 45 min.
Preheat oven to 450F and bake 25-35 min.