Why not try a DVD first? My friend and I did YogaLates (a yoga-pilates) hybrid that had very similar positions but didn't have the spiritual aspect to it. (They build up a killer core. Ouch!)
I do like just taking deep breaths and doing some of the poses once in a while, without the spiritual aspect to it. It helps me relax. I don't quite know about my health problems being alleviated, but I don't do it so often.