A Shopper's Guide

There are eight major schools of yoga, from Bhakti, which is mostly about prayer and mantra chanting, to Tantra, which is largely about sex. Most yoga studios and fitness centers in America teach some type of Hatha yoga, the yoga of activity. Hatha comes in hundreds of different flavors--each emphasizing different body postures and breathing techniques. These are some of the most popular:

EASY

--Iyengar A good place for beginners to start, Iyengar concentrates on carefully aligning the body, using straps, blocks and pillows to help students who lack flexibility. Useful for physical therapy because it focuses on the movement of the joints.

--Kripalu Sometimes called the yoga of consciousness. Students learn to focus on their physical and psychological reaction to various postures. There are three stages: learning the poses, holding the poses and combining them into a kind of meditation in motion.

--Kundalini Also appropriate for beginners. Practice involves the classic stretching postures and breathing exercises, coordinated with chanting and meditation to stimulate the release of so-called Kundalini energy. --Viniyoga This is the most highly customized form of yoga. Viniyoga teachers cater stretching postures to individual student needs and abilities. Function is stressed over form, with an emphasis on integrating the flow of the breath with the movement of the spine.

MODERATELY DIFFICULT

--Sivananda One of the world's largest schools of yoga, Sivananda calls for the rigorous application of yoga postures, breathing exercises, relaxation, vegetarian diet and study of scriptures. May require lifestyle changes.

CHALLENGING

--Ashtanga (Power Yoga) For those looking for a serious workout. Students jump from one pose to another to build strength, stamina and flexibility--all the while practicing breath control. Best for athletes and dancers.

--Jivamukti A variation on Ashtanga with an emphasis on spiritual training, including chanting, meditation and readings. Currently popular with celebrity devotees, including Madonna and Christy Turlington.

--Bikram or Choudhury (Hot Yoga) Hot and sweaty. With the thermostat set to 100[degrees]F or more, students are led through 26 postures "scientifically" designed to stretch muscles and tendons in a certain order. The heat warms the muscles, helping them stretch farther. One of the newest variations, this one is not for the faint of heart.

SIGNING UP To find a class near you...

Whether you are looking for a teacher in your neighborhood or a place to take classes when you are on the road, the best way to find the yoga center nearest you is to go online. Here are some particularly useful websites:

YOGAJOURNAL.COM The Yoga Journal's website provides a detailed directory-and-source guide

YOGASITE.COM Offers a state-by-state listing of yoga teachers

YOGAFINDER.COM Their handy search engine can locate sites by state or by instructor's name

YOGADIRECTORY.COM Includes links to the websites of hundreds of teachers, centers and retreats