Phonegap Beginner's Guide by Andrew Lunny delivers exactly what the title promises as it is a good guide to developers just getting started with PhoneGap. The book walks you through the installation of the PhoneGap framework, shows you how to develop and debug your application in a web browser before bringing it over to the device and describes a number of HTML5/CSS3 features you can take advantage of without even needing PhoneGap. Then the book walks you through a number of areas of device functionality that the PhoneGap API like the accelerometer, camera and contacts. Plus there is a chapter devoted to extending PhoneGap functionality using the Plugin API.
The only con that I can point out is that the book does not completely describe the available PhoneGap API, nor should it really as it is targeted at beginners. I can't fault Andrew at all as a lot of the currently functionality was delivered after the books was sent to be published. One thing you should be aware of is that chapter 9 describes the navigator.service.contacts interface which is now navigator.contacts.
I do recommend this book for PhoneGap and fledgling hybrid mobile application developers. Probably the easiest way to get it is as an ebook from Packt.