B.G.
There are tons of books and the internet makes it so easy to find them. I used to work at a book store in the children's section and these are the books I could remember.
1. Brendan and Belinda and the Slam Dunk! by Anne Rockwell(she has a series on sports)
2. Cork and Fuzz by Dori Chaconas(If I remember correctly this is a series as well)
3. The Last Place Sports Poems of Jeremy Bloom(This book is great, kids learn about poems in kindergarten)
4. Oh Beans by Ellen Weiss
5. Good Sport Bad Sport by Jerry B Jenkins
6. There is also a sports series by Matt Christopher, he writes chapterbooks.
7. The Berenstein Bears
You can go to amazon.com or barnesandnoble.com and type in good sport and see what comes up. Good luck. I hope this helps.