I've found most of my cookbooks in the adjoining store to the Art of Disney store in DTD. I know a new one came out earlier this fall, and I'm planning on picking one up tomorrow. I leave at 3pm today. And I can't wait. Making my shopping list up right now.
I believe there is only 1 wdw park cookbook-- The new one came out recently (last 6 months) and has a blue and white color. The older one (which you may still be able to find) has a a red and white cover, had been out for a few years. They can be found in most gift shops and definately at DTD in the bookshop and at World of Disney (if you have an AP you get 10% off) I once saw another cookbook in a gift shop in AK and haven't ever seen it again, this was about a year ago. I believe it was a specialty cookbook, big square and color photos.
I kinda collect disney cookbooks and recipes.. ebay is also a great place to find old ones.