Put the warm water in a medium bowl, sprinkle the yeast over the water and stir. When it starts to bubble, add the flour and start to stir with a wooden spoon (or by hand). Add the olive oil slowly until the dough is pliable and smooth. Work in the feta cheese, kneading until evenly distributed throughout the dough. Cover the dough and let it rest for 30 minutes.
Place the dough on a lightly oiled cookie sheet and flatten with the palms of the hand. The dough shouldn't be any higher than about 1 1/4 inches. Score the top lightly in squares or diamond shapes. Cover with a towel and allow the dough to rise for one hour.
Preheat the oven to 340F (170C).
Bake for approximately 30-40 minutes. It should be done on the bottom and nicely browned on top.