For all the folks like me who are waiting the Mapping Hacks book by Jo Walsh and Eric Schuyler, there is a blog about it.

"GPS units are nearly everywhere, integrated into cars and even mobile phones. With this collection of mostly free techniques, you can create and share useful digital mapping services of your own. Find the best sources of public geographic data, collect your own data, and integrate that information into the maps you make. Learn to use maps in weblogs, photo galleries, interactive applications , and more."