Yoga is extremely good for you. It improves the strength and flexibility of the muscles that support the spine and improves posture (giving a slimmer appearance) by strengthening back and abdominal muscles. It makes the body more flexible and helps you relax even in the midst of a stress stricken environment. This is one of the foremost reasons why people want to start practicing yoga - to feel fitter, be more energetic, be happier and peaceful. I've pasted a link below that outlines the benefits in more detail of practicing yoga. The link also has suggestions for people who live a very busy life to begin practicing yoga. Enjoy!

http://www.abc-of-yoga.com/beginnersguide/yogabenefits.asp