At first, you may not think they would go together, but I used his books quite a bit this past year in my preschool Spanish classes. The first one was Oso pardo, oso pardo ¿qué ves ahí? which covers colors and animals. What preschooler doesn't enjoy learning about these two subjects?
First I scanned the images and then printed them on magnet paper. We talked about the animals first. I asked the children if they had un gato (cat), un perro (dog), una rana (frog) and so on. While many answered yes, I didn't have anyone say that they had un oso at home. Go figure. *grin* As we talked about the animals, I would place a picture of each on my magnetic/dry erase board. Then I would read the book.
If you wanted to go further, you could sing Que llueva from Diez Deditos. You could use the animals from the book and place them in la cueva (cave) made out of crumpled up construction paper. Also, you could simply draw a cave on the dry erase board and stick each animal "inside" it. Reinforce by asking "¿Qué ves en la cueva?" The child can either say the animal or the entire sentence, " Veo __________ en la cueva."
I also use this book to introduce colors. All I pretty much do is constantly use them in context as we talk about the animals and read the book. In upcoming lessons, I'll use colors to describe everything. Before too long, the children are telling me about the colors. For instance, I was reading another book, when one little boy piped up and proceeded to tell me the colors he saw on that page. It becomes a part of their vocabulary. One thing I don't do is translate into English. I point to the object and say what it is in Spanish. Evidently is does sink in.
Another post about Eric Carle.