Easy Microcontrol'n is a great beginners books for PICmicro users.
The PIC Microcontroller Projects book features 12 complete PICmicro projects in easy to understand BASIC.
This is a recent addition to the Tab/McGraw-Hill lineup on how to use an AVR microcontroller. The AVR datasheets are fine, but they're not as useful as this book!
The Programming & Customizing the PICmicro book is a book for beginners and features 12 project and 30 experiments.
Mechanical Devices for the Electronic Experimenter covers numerous mechanisms for robotics and electronics applications. A great resource for brainstorming!
This essential title in McGraw-Hill's ROBOT DNA SERIES is just what robotics hobbyists need to build an effective drive train and gain a full understanding of robot locomotion.
Gordon McComb's Robot Builders Bonanza - 4th Ed. is considered by many to be the bible of hobby robotics.
This book walks you through the essential skills you need to build and control devices using the Propeller chip and its parallel processing environment.
Just recently find out about MAKE Magazine? I bet you're scrambling to find back-issues. Or stealing your friend's copies, and "conveniently" forgetting to return them.
Microcontrol'n Apps is an intermediate book on PICmicros.