At many of these places, you can order online at a discount:

My local bookstores:
Schuler Books, Lansing/Grand Rapids link to the books
Pooh's Corner, Grand Rapids link to the store
Tuesday Books, Williamston link to the store
The Reading Tree, Grand Rapids link to store

Cool national indie bookstores:
Flying Pig Bookstore, Vermont link to the books
Powell's Books link to the books - order online!
Indie Bound  link to my books page

The chains:
Borders book 1, book 1 paperback, book 2, book 2 paperback, book 3
Amazon.com link to book 1 - link to book 2 - link to book 3 includes reviews
Barnes & Noble link to the books

My publisher:
Bloomsbury link to my author listing & book info