Here are some books I like to recommend for all interested in nature photography.

John Shaw: One of the best nature photographers and one of the best teachers too. This book is a new, updated version of his first book.

Niall Benvie: The best nature photographer of Scotland. Great photos and a lot of "how to" improve your pictures with photoshop.

Arthur Morris: "The Art of Bird Photography". The best bird photographer tells you everthing about equipment and how to use it in the field.

NaturFoto: Monthly german magazine that deals with nature photography. I think they make a english version too.

Outdoor Photography: Monthly UK magazine focused on landscpape and travelphotography in Great Britian.