My Yoga Online (http://www.myyogaonline.com) is a payed online video and audio database that has been in subsistance for 4 years. While their is a monthly subscription fee, My Yoga Online does offer a wide variety of teachings and lessons on the practice of yoga, taught by teachers from around the world. They also have a download section so you can use their programs on your portable media players like an ipod or portable video player.

If you do not mind paying for online tutorials, My Yoga Online is a good place to go for video instructions and online teachings.