It is donation-based, aka free if you can't afford it with a suggested donation of $10, and is open to everyone. The concept is pretty cool and the classes were actually some of my favorites ever. We rocked out to the Beatles and Jack Johnson while still maintaining the core integrity of the sport.
They have studios in both Berkeley and SF, although I haven't been to either. My favorite local one is Yoga Source in Palo Alto, although they can be a little pricey.
Do folks have other recommendations? I know there are plenty more out there...