My whole family loves yogurt and once I found out how easy it is to make I quit buying it (unless I have to for new starter). You don't have to have any special equipment and there are instructions on the web for making it with things you probably have in your house already, but I went ahead and purchased a 2 liter capacity yogurt maker by Yogourmet. Here is a link to Amazon where you can purchase one for a reasonable price.
Yogourmet Electric Yogurt Maker
What you need:
1/2 gallon milk (I use 2%)
1/2 Cup nonfat dry milk (only because I don't use whole milk)
1/4 Cup starter yogurt (use a good one until you have your own, like Brown Cow)
In a heavy saucepan stir the dry milk into the other milk and heat to 180 degrees F. Maintain this heat for a couple of minutes. You will need to use a thermometer that clips on the side of the pan. The Yogourmet comes with one. I keep stirring so it doesn't burn to the bottom. Living at high altitude, this takes a long time to bring it to this heat.
Cool the milk to 110 degrees F. I put about 1" of water and ice cubes in my sink and put the pan in it to cool it more quickly. Take about 1/4 C. of the cooled milk and stir it into the starter. Any hotter than 110 deg. and it will kill the yogurt cultures. Pour this mixture into the inner container of the yogurt maker and then pour the rest of the milk into it. Put the cover on securely. Put lukewarm water into the outer container of the yogurt maker up to the indicator line. Insert the inner container into the outer one and plug it in. I "process" it for about 7 hours. Put the yogurt into container - I use quart canning jars and refrigerate.
That's all there is to it.