First, you can go to this website and get major info overload...but it's THE resource for Kefir info:http://ftp.newave.net.au/~dna/kefirpage.html
He has many links and offshoots....so after wading through that, try the first part of the 'Got Kefir' Thread, which is basically alot of the info distilled down, plus a plethera of recipes and ways to use up your Kefir.
PM Gale Force (who has plenty of spare atm), or me in a week or so (I ran out), and we can 'hook you up' with some Kefir Grains via mail.
Basically, you add whole cow or goat milk to a glass jar, either room temp or cold, pasturized or not. You add in your Kefir grains (a misnomer, they just look like grains, they are a symbiotic colony of bacteria and yeast like you have in yogurt) and cover loosely with a lid. You let this jar sit on your counter top about 24 hours (summer and winter months will make it brew faster or slower depending on temp in your kitchen).
When it's brewed, you strain off the 'Kefir Milk' which is now thick like a drinkable yogurt, and start over with fresh milk and your grains to brew more.
You will get an info sheet with your grains that covers this.
It's really easy, and even if you only brewed a cup or two a day, you can see how you could quickly have too much Kefir, ergo, the recipes listed in the 'Got Kefir' Thread.
If properly taken care of, the grains can last you forever...they will reproduce and grow in numbers....you might find yourself shipping the extra off to friends yourself!