Have just arrived, but have noticed a lack of yoga places in Zurich (and there seams to be nothing in Zug), but have found an interesting place.

PlanetYoga: About Planet Yoga - Planet Yoga - Anfänger Yoga, Yogaschulen, Yogakurse, Yoga Zürich, Schwangerschafts Yoga, Hatha Yoga

Have thought about doing a teacher training with the this May, but sadly my German (or absence of it) would not allow me to participate, but did seam to have a pretty good

http://www.yogazurich.com/index.php?lang=en

Let me know if you find anything else.