I love making my own yogurt. We save $1.75 per quart by making our own. My recipe is:
4 c. milk
1/4 c. nonfat powdered milk
2 Tbsp starter yogurt
Combine milk and powdered milk, bring to a temp of 180 degrees F (or until tiny bubbles start forming around the edges of the pot, but not when it boils over!), and then cool to 110 degrees. Right around 115 degrees, take a ladle or two of warm milk, combine it with the starter yogurt in a separate dish, and recombine in the milk in the pan. Pour the mixture into a container, and then place in a cooler surrounded by jars of warm water, or into a water jug that fits the container. Let sit for 6 hrs, and you will find the most delicious, creamy, tangy yogurt you've ever tasted (hopefully

)!
Jenni
http://lifefromtheroof.wordpress.com/2008/09/17/favorite-frugal-recipes-easy-homemade-yogurt/