Check out “Mapping Hacks,” a new book on the O'reilly list by Schuyler Erle, Rich Gibson, Jo Walsh .
“Mapping Hacks is a collection of one hundred simple techniques
available to developers and power users who want to draw digital maps.
You'll learn where to find the best sources of geographic data and then
how to integrate that data into your own creations. With so many
industrial-strength tips and tools, Mapping Hacks effectively takes the sting out of digital mapmaking.”