Caught this thread and thought I might reply.
Indeed, the fourth edition of Robot Builder's Bonanza is due out soon, but the details about it on Amazon are very out of date. They should be updating it (and the cover, which is completely different) pretty soon, but in a nutshell, cr0sh is correct that it drops a bunch of old stuff to make room for new stuff -- specifically Arduino (yeah!!) and some PICAXE.
RBB4 isn't an Arduino-specific book (doing one of those now), but it has numerous code examples for Arduino, and relies on it as the primary processor for the various projects involving a microcontroller. Pretty soon I'll be able to post an updated table of contents on my site, but I have to wait until the publisher "goes live" with their version first.
Looks like Robotshop is reprinting the whole series of SERVO Magazine ArdBot articles, though trailing a few issues back. The series is up to Part 6 in the magazine (out of seven parts), but RobotShop has just the first four at the moment. They're listed here:http://www.robotshop.com/articles.html
under the Electronics heading. My guess is that eventually they'll have all seven.
Be sure to also visit my Web site at robotoid. com for ArdBot construction notes and errata.