Here is summary of answers above:
- Book page: http://shop.oreilly.com/product/9780596005900.do
- LDD3 officail site to download book free version: http://lwn.net/Kernel/LDD3/
- LDD3 official sample code to download: ftp://ar.linux.it/pub/ldd3/ldd3-samples-1.0.0.tar.gz, http://examples.oreilly.com/9780596005900/
- LDD3 book online version: http://www.makelinux.net/ldd3/
- LDD3 sample code which keep updated and works with latest kernel: https://github.com/martinezjavier/ldd3
- Florida State University Linux Kernel & Device Driver Programming course
