There are a number of books published (and soon to be published) about Mobile Design. Here’s a quick summary of what I’ve come across recently:
Mobile Interaction Design by Matt Jones, Gary Marsden
“Jones and Marsden provide a high level yet tangible way to design within typical mobile constraints like low power, small screens, keypads, and more.”
Mobile Usability: How Nokia Changed the Face of the Mobile Phone By Christian Lindholm, Turkka Keinonen
“A look at the history and background of the Nokia mobile phone design.”
Handheld Usability by Scott Weiss
“Handheld Usability is the first book to cover the emerging field of handheld product design. The book covers everything from product design cycles to optimum menu length and audicon (audio-icon) characteristics.”
Designing the Mobile User Experience by Barbara Ballard
“Barbara Ballard describes the different components affecting the user experience and principles applicable to the mobile environment, enabling the reader to choose effective technologies, platforms, and devices, plan appropriate application features, apply pervasive design patterns, and choose and apply appropriate research techniques.” Prior to the release of her book, Ballard has started a wiki on Mobile Interface Design Patterns.
Mobile Web Design By Cameron Moll
“Much has been written about mobile devices. Much has been written about developing websites for the so-called "standards era" of the web. However, little has been written about the two colliding. This book aims to fill that void.” Prior to the release of this book, Moll has begun an article series on Mobile Web Design.
The Mobile Connection: The Cell Phone's Impact on Society by Rich Ling
“The Mobile Connection has the feel of a guidebook to the mobile phone and its place in shaping and being shaped by our social world.”
Designing Software for the Mobile Context: A Practitioner's Guide by Roman Longoria
“The first part deals with the role of design and development of mobile platform technology and mobile application design. The second part deals with designing enterprise and consumer applications.”
Designing for Small Screens by Studio 7.5
“Outlines the basics of designing for mobile screens.”
Mobile and Wireless Design Essentials by Martyn Mallick
“Describes mobile and wireless design techniques from a software developer's perspective.”
Developing Mobile Applications: Design Principles for BlackBerry Browser Applications (PDF) by Research In Motion
“Provides an overview of design principles for developing mobile applications and suggests ways in which you can apply these principles when you create applications for BlackBerry devices.”
Nokia Usability Resources by Nokia
"A variety of excellent Nokia mobile UI resources." (thanks Barbara Ballard)