The most helpful book I've found is "Yoga for Dummies".
my Wii Fit
I'm going to have to get that. I have sprained/strained my SI (sacroilliac) area twice in the last 18 months, and need to get a handle on it before its too late. Some core strengthening, stretching and flexibility, and a little weight loss (love belly) should get me headed in the right direction.
We have that too, though I haven't yet tried it.