Yoga is both an excellent re-introduction to exercise for those looking to get back inot shape, and an effective complement to any existing workout regime.  Probably the best layman's introduction to yoga that I have read was the following article from CBC:

http://www.cbc.ca/news/background/exercise_fitness/yoga.html

Throughout my journey into the practice and treasure of yoga, I have been inspired by some of the extreme athletes who have used yoga to push themselves to the competitive edge of their sport.  From NASCAR drivers to NHL goalkeepers, yoga is truly for EVERYONE!