Just a few quick comments on Sonnons stuff.
I've done Yoga for Blokes, Bikrams and Scott Sonnons Intu Flow and Prasara.
Out of all of them, I have personally found Sonnons stuff has had a bigger improvement on my performance than anything else I've tried.
Most of the Yoga I had done up to that point had involved moving into poses and holding them. I saw improved -flexibility- very quickly.
Sonnons stuff is more about moving between the poses rather than the poses them selves and I saw improved -mobility- very quickly.
Trying to learn Sonnons stuff from the internet is very difficult. I tried it and just could not 'get it'. I then took one of the 3 day CST courses, and its slowly falling into place.
If your just starting out, then I would urge you to buy the Intu Flow DVDs. They are very well done and you can easily pick up the basics in your own time. The ebook is a good reference, but you need to see the movements to be able to follow them.
Everyone I know that has tried Intu Flow has found significant improvements in their mobility. After 6 months of 10 min practice per day I almost have the same range of motion as my 4yr old daughter again.
I do Intu flow as part of my CF warm up.