Kimchee, at its most basic, is pretty much the same thing as sauerkraut - naturally fermented pickled cabbage. Other ingredients, such as garlic, hot red pepper, and fish sauce, are optional and vary from region to region and maker to maker in Korea.
The local Japanese-Korean restaurant I go to serves a kimchee that I really like - very spicy. It is a bit of an acquired taste, though, to be sure.
The owner of my local Korean restaurant makes her own. Heavy on the garlic and hot peppers.