When I was in BsAs, I went to http://buenaondayoga.wordpress.com/. I would say that if you're looking for something that pays a great deal of attention to the more "spiritual" side of the practise, this one most likely isn't for you—however, I never am, and in fact find excessive chanting and...
If you're in San Telmo, try Buena Onda for yoga—they're super-nice ladies, and classes are held in both English and Spanish.
http://buenaondayoga.wordpress.com/