Yoga Stretch ($1, iOS): This app includes traditional and Vinyasa flow poses, allowing you to create and save up to five custom yoga sessions. Not only can you play your own iTunes music in the background, but you'll also have an audio instructor to guide you through the practice.
Daily Yoga (Free with in-app purchases, Android and iOS): With more than 400 poses and 50 yoga classes, this app is a no-brainer. Video and voice instructions guide you through beginner, intermediate, and advanced levels so that every yogi can participate.