This fall, I am teaching a pre-school (4-5 year olds) yoga class, which has been super fun. It took the kids 1-2 sessions to settle into our routines, and now they are just really engaged and excited about both the books and the asanas.
For this class, we read the book Fat Cat by Margaret Read MacDonald. I LOVE this book for all of the language concepts included - specifically rhyming, sequencing, and phonemic awareness (of the /f/ sound). Its also a perfect read aloud because of the reoccurring refrains that allow kids to chime in and help "read" the book. In addition, Fat Cat is a really fun book to act out - the characters and all of their different movements (i.e. marching, clomping). Ideal for a pre-school yoga class!
A quick note: I included a "play" option in the lesson plan. I didn't end up with enough time in this particular class to include the play activity - but I have done it many times before with this age group and it is ALWAYS fun.