Excellent introductory book: Computational Geometry: Algorithms and Applications, Second Edition (the four dutchmen book! :D)
It ignores low-level problems (accuracy, degenerate cases - and rest assured that applied computational geometry is fraught with these), and focuses on the concepts. Very easy to follow book, enjoyable, many diagrams run on the sides of the book, just next to the text that describes them, and it contains quite a variety of problems along with examples of real applications.
I believe this is the best introductory book on computational geometry all around. Strongly recommended!