Kombucha is actually a combination of different elements, which include lichen, bacteria, and yeast. The mushroom itself is not eaten. Rather, a tea is made by fermenting the mushroom for about a week in a mixture of water, sugar and green or black tea, with apple cider vinegar or a bit of previously made tea added. The mushroom can be kept in that mixture to reproduce "daughter mushrooms." These daughter mushrooms can be used to produce more tea.
Kombucha is believed to be a natural energy booster and detoxifier that may also help slow or reverse the aging process and may help fight serious diseases like AIDS, cancer and multiple sclerosis.
I am happy with my Yogi Green Tea Kombucha, but for those of you who want to try brewing kombucha at home, you might want to check out the following:
Kombucha Brooklyn sells Kombucha Home Brew Kits.