It isn't a product that you can buy in the store (yet), but simply yogurt that has had the whey drained off.  The resulting "cheese" can used when making reduced-fat desserts, such as cheesecakes.

Ingredient: Four cups (one thirty-two-ounce container) plain yogurt 

Method:

1. Line a wire strainer with paper towels or a cheesecloth, and place it over a deep, medium-sized bowl.  Be sure the bottom of the strainer clears the bottom of the bowl by 2 or 3 inches.

2. Spoon yogurt into the strainer and place a paper towel or more cheesecloth on top.

3. Place a saucer or small plate in the strainer to lightly weight the yogurt. If you are not in a hurry, do not weigh the yogurt with the saucer, and refrigerate the whole setup overnight to slowly drain the whey.

4. Let stand in the refrigerator until about two cups of the whey has drained off, and the yogurt is thick and somewhat firm, about one and a half hours.  (There are also cheese making contraptions that are available at kitchenware stores.)  

NOTE:  If you hate to discard the tangy whey, some frugal cooks use it in soups--but do not use it as a substitute for liquids in a baked recipe.

Sarah Phillips, The Healthy Oven Baking Book, Doubleday, 1999