The Korean From Zero E-book is a great resource for beginners looking to master the basics of hangul, pronunciation, and elementary sentence formation. The simple and straightforward organization of the material and categorization of concepts aid the reader in quickly learning the Korean alphabet and using them in basic sentences. The additional audio resource is a great tool for understanding and practicing pronunciation.
I am currently using this book and find it to be an amazing introductory tool for beginners in the language. And best of all, it's free!