This is a great source for yoga books and reviews. My wife and I started yoga about 3 months ago. We started out with this site and we love it. Hope you do too. Good luck!
One of the issues you'll find is as that the subject matter is sooooo old, there is alot of information out there on it. Also the language and culture gap creates challenges too, Yoga in Sanskrit basically translates to "union," so yoga is really more of a philosophy on life than simply a daily practice of specific body poses.
As noted, when most westerners think of Yoga (meaning only the poses and streching) they are really thinking of Hatha Yoga or physical yoga. All the different "studios" you read about are for the most part simply practicing different styles of Hatha Yoga. http://www.yogabasics.com/learn/hatha-yoga-the-physical-path.html
No doubt studios do exist that practice other Yoga forms, but Hatha is by far the most popular here in the States. Naturally I'm not as familiar with what is preferred across the pond. Good luck.