I am just starting the milk Kefir making. I used to use store bought.
Here is some info on making milk kefir
Here is a nice short video on how easy it is to make Milk kefir
http://www.youtube.com/watch?v=DzkCDnt2KpI&feature=related ( i love the music for this one lol )
Here is the link to the Kefir lady, She seems to be a good source for the grains. I found that I can find grains from Amazon, ebay just as easy though.