My book on contributing to and using OpenStreetMap is now available to buy:

https://www.packtpub.com/openstreetmap/book

It's available in both printed and ebook formats, and there's a discount if you buy both together.

The book itself is intended to be an introduction to a wide range of OpenStreetMap tools and techniques for the less-technical user. It takes you through how to get started with the site and community tools, basic surveying and editing techniques (using Potlatch, JOSM and Merkaartor), spotting problems in the data, producing your own maps and customised data sets.

There's an article based on a chapter of the book here:

http://www.packtpub.com/article/getting-started-openstreetmap