Doreen Cronin's Diary of a Fly, Diary of a Worm, and Diary of a Spider are among my favorites. These books are written from the animal's point of view, and they are both entertaining and informational. After reading, there are many activities that can be done with these books such as creating a calendar to keep track of the daily happenings of each creature, create a diary of another animal to mimic Doreen Cronin's style, or compare and contrast the characteristics of each character.
You may want to visit my classroom website where I have adapted a Webquest to fit the needs of my students. You can find it here !