I've decided to remove the booklet from the website because I haven't updated it in more than a year and it's full of little mistakes, parts are missing, some examples don't work properly anymore.
There is a Getting started" section of the website that works better and it's much more updated.
If you want something similar to the booklet , I've written a book that is inspired by it but greatly expands it (the booklet was 30 pages, the book is 128). You can find it here http://oreilly.com/catalog/9780596155513/
Massimo ( m.banzi [at] arduino.cc )