If you would like to know more about what yoga is, you can download this application which, although not very comprehensive, will provide an introduction to the discipline.
You can get information about yoga traditions, instruction, articles, asanas, which are body position, and the sun salutation via the six chapters on the left side of the main frame.
The navigation of this e-book is not extremely pleasant, but I liked the idea of the progressive photos to explain how to properly execute the sun salutation.
It would have been good to have the same type of images for all the asanas named in the previous chapter.
If you are interested by yoga and would like to read articles on the discipline and its history, give Yoga Freeware a try and practice the sun salutation to begin with.