Links:

What is Yoga? http://en.wikipedia.org/wiki/Yoga

About Yoga -http://yoga.about.com/

Yoga Basics - http://www.yogabasics.com/

Vinyasa Flow Yoga - http://yoga.about.com/od/typesofyoga/a/vinyasa.htm

Yoga Poses - http://www.yogajournal.com/poses/finder/browse_categories