It can be transliterated into English letters in a number of ways. Kabbalah is the usual way of transliterating the word in Judaism. Learning Kabbalah in a Jewish context means honoring traditional Jewish ethics. Intention is extremely important. Kabbalah is about healing, both personal healing and being part of healing the world.
Study is grounded in Judaism and Jewish community.
In the article, Hammond describes a Cabalistic tree. This is a warping of the Tree of Life from Kabbalah. Many of the rabbis in the Virtual Yeshiva include Kabbalah in their teachings. Most of them are part of Reconstructionist Judaism and Jewish Renewal. For a more traditional Chassidic approach, try the Chabad Lubavitcher site.