Navaho Legends is one of the earliest collections of Navajo oral traditions in English, and still the best. Originally published in 1897, Washington Matthews’s sensitive translation contains extensive versions of the Original Legend and two other tales. These richly detailed legends remain among the most complete sources of Navajo cultural, ritual, and ceremonial information.
This edition is fully faithful to the original, containing Matthews’s introduction, extensive notes, interlinear prayer translations, musical notations, and index, plus a new note on orthography by Robert Young.
I picked up a $0.99 Kindle edition of this book because my friend David wants to create a Navajo-culture-based stage production and asked for my help (he writes music, not stories). It's in the public domain, so I'm sure you could find it for free somewhere. It looks like maybe you can get it at Google Books, but the cover is different from this edition and it's called "Volume 5," so I'm not sure. There is also this cool free book The Dîné: origin myths of the Navaho Indians that I haven't gotten into yet.
Although the book took me a looooooong time to get through, it was well worth my time. It contains a version of the very lengthy Navajo creation legend as well as some stories about Coyote, Estsanatlehi (Changing Woman), and many others. With so many characters and legends and my desire to understand it well, it was a bit hard to follow and I frequently had to go back and read sections over again.
At this point, I plan to adapt a couple of stories to go with my friend's production, respecting Mr. Matthews' request not to distort the legends or characters with foreign thoughts or culture. For that reason, it will be a very close adaptation.
Overall impression: It is kind of awesome that Coyote enjoyed getting his eyes taken out, tossing them into the air, and catching them back in their sockets. The book was full of moments like that--things that were very different from my cultural background, but that for that difference were infinitely interesting and absorbing. It's definitely an older writing style that covers a lot of events and is not easy going, however.