How to Make Tofu

Food: Seen in today's Houston Chronicle:

1. Soak raw soybeans overnight.
   
2. Grind, boil, and strain the soybeans to produce soymilk.
   
3. Add a coagulant to the soymilk, which causes it to separate into curds (the solid part) and whey (the liquid part). Drain the mixture in molds and weight it.
   
4. Cook it and eat!
   

Now, I wonder--Does this mean that you can simply take soymilk and coagulate it? I'm all for saving myself the first two steps. And what is used to coagulate the soymilk?