I just discovered this great website that has free yoga classes: www.doyogawithme.com
The great thing is you can use them online or you can download the class or buy the DVD. Not all the classes are available in all the formats.
What I found interesting is that, at least the routines that I have done, are absolutely excellent, as is the instruction; much better than many of the DVDs available for sale. The difference is it's not perfectly produced with perfectly-shaped people. But I actually really like that aspect of it; I like the genuineness.