Practice Yoga has some beginner classes -- schedule here:
Practice yoga studio, Yoga classes and Workshops in Philadelphia. (you want the Level 1). And while I wouldn't say that Practice is particularly "beginner friendly" (even in the beginner classes, you'll get a fair amount of advanced students), one of the things that I like about Practice is that they definitely use straps, blocks, etc. appropriately for beginners who are not yet limber or strong enough to do the formal positions. It has been my experience that this doesn't happen in, for example, beginner classes at a gym, so that beginners either get frustrated that they can't do the poses or risk injury trying to do them.
Yoga for Beginners
