Here's a great resource for those looking to trim their yoga budget by practicing at home: Yoga-Poses.com is an index to free yoga videos available on YouTube. What's great about this site is that you can browse by pose name, difficulty, or yoga style. Do keep in mind that the yoga videos on YouTube vary quite a bit in the quality of instruction. For a few videos vetted by yours truly, check out About.com's yoga video offerings.

Great resource, thank you!
Exactly what I was looking for
For instructional videos in the Iyengar tradition, taught by Senior Iyengar Yoga Teacher, John Schumacher, watch the playlist created by iHanuman.
I found a great free yoga site called myfreeyoga.
Those are great, but I found the quality on My Yoga Online is a lot better and it’s not expensive. Definitely worth it. I wasn’t really sure if I should join or not, but I read a review of My Yoga Online on http://www.internetyogaclass.com and I’m so glad I did!
I wasn’t sure if I should spend any money, but I read the review at http://www.internetyogaclass.com about My Yoga Online and I’m glad I did. While the videos aren’t free, they are really the best quality out there, and it’s still really inexpensive!
http://www.yogatailor.com is another excellent resource for online yoga videos. They have a unique approach. They have removed the clutter typical of yoga websites and made a simple menu driven approach. They create custom yoga videos on the fly based on the user’s criteria. The videos change daily and they adapt based on the user’s progress. The videos are consistent and you feel like the classes are connected . For the price of a single trip to the studio, you can enjoy a month’s access to the website
I have a question, instead of a comment and would be grateful for any comments anyone could lend me: when trying to find, hold and deepen asanas that require balance do you think it would be beneficial to practice the posture without an aid to improve balance or would it be better to use a prop, for example, a chair? I’m asking because I have weak ankles,for which I have recently begun exercises and I find that I am unable to hold even the simplest one-legged balancing posture for even a few seconds. (ex. tree,dancer, warrior III – and even worse when I need to rotate my upper body so that I look up towards the ceiling – such as half-moon. Think I should work the technique unaided (which should surely improve slowly over time, I’d think) or prop myself up?
What a great resource about yoga
What a great resource! Article about yoga video
HutZai, use props until you find your strength. No need to struggle. Try Iyengar classes. Some people including teachers use props all the time.