In order to make my own yogurt my mother-in-law bought us the Euro-Cuisine Yogurt Maker from Williams Sonoma (she works there!). You could make it without the yogurt maker but the yogurt makes is so easy for a busy working mom.
First bring about 32 oz. of milk to a boil over medium to low heat. (whole, skim whatever you want - I am sure you could also try substituting soy milk as well - I need to try that!).
The milk needs to heat up to 185F and stay there for a couple of minutes. Make sure you are stirring so it does not stick.
Next cool the milk down to room temperature. If you are in a hurry place the sauce pan in a bowl (or the kitchen sink) in a cold water bath.
After the milk has cooled down stir in 7 oz of yogurt (according to the directions you can use homemade yogurt but once do this one time then use store bought the next time - it has something to do with the cultures).
Once the milk and yogurt is all mixed up pour into the jars that come with the yogurt maker, turn the yogurt maker on and let it work for the next 12 to 15 hours (I use the 15 hour button).
Once the machine is done chill the yogurt in the fridge for 3 hours, and then enjoy. You can add fresh fruit, honey, granola, whatever you want!