At our house, our son's favorite was Alona Frankel's Once Upon a Potty -- a simple and fun little book about a boy named Joshua and his first attempts at using his potty. Whether or not it was actually successful in helping our son master potty training is debatable. Certainly, it was a nifty little impetus that helped our cause.
There are so many books out there which can introduce potty training in an easy and approachable way. Here are some of our favorites...

• Once Upon a Potty by Alona Frankel. Available in boy and girl editions.

• Everyone Poops by Taro Gomi.

• Too Big for Diapers by Random House.

• Lift the Lid, Use the Potty by Annie Ingle.
Which ones are we missing? What potty training books for kids do you recommend?
Comments (7)
A Potty for Me! by Karen Katz
A second that... A Potty for Me! should be at the top of the list!
We had Lift the Lid, Use the Potty plus one by Mr. Rogers. Despite all the resources, my son was almost four when he finally started using the potty. Sigh.
Another vote for "A Potty for Me". My twins love it!
We have "Time to Pee!" by the always great Mo Willems.
My two year old can practically read A Potty for Me! by herself she loves it so much. "Reads" it to herslef while on the potty all the time :)
I second kellyjeanie's suggestion of "Time to Pee!" by Mo Willems. And for the parents, I recommend "Diaper-Free Before 3: The Healthier Way to Toilet Train and Help Your Child Out of Diapers Sooner" by Jill M. Lekovic, M.D.