Another book I like to use is La oruga muy hambrienta (The Very Hungry Caterpillar) by Eric Carle. Using this book, you can cover the days of the week, different types of foods, small/big, to be hungry and other themes.
For my preschool class, we mainly talk about the food:
la manzana - apple
la pera - pear
la ciruela - plum
la fresa - strawberry
la naranja - orange
la sandía - watermelon
el pastel - cake
el barquillo de helado - ice cream cone
el queso - cheese
la paleta - lollipop
Using my dry erase/magnet board and pictures printed on magnet paper, I first show them the food listed above. Then we talk about the useful phrase tener hambre (to be hungry). We also talk about which foods are healthy and not healthy (saludable, no es saludable). After they have a good grasp on the new words, I then read the book using the kit pictured (item # LA988) from Lakeshore Learning.
For the cocoon (el capullo), I roll up a piece of brown construction paper large enough for the puppet to fit inside. While it's inside, I make it so the butterfly comes out, but not the caterpillar (the butterfly is attached inside the puppet) - only comes out at one end. Every time I do this I get ooos and ahhhs. *grin* Then they would always ask me how I did it and to please read the book again.
For more ideas about using Eric Carle's books in class or at home, visit the Caterpillar Exchange Bulletin Board on his official web site.
Here's an earlier post about another Eric Carle book.