For more background information about the shakuhachi, its history, making, different schools, etc, here are some links:
The International Shakuhachi Society: www.komuso.com
The European Shakuhachi Society: www.shakuhachisociety.eu
Shakuhachi Resources: www.shakuhachi.wikidot.com
Komuso Blog: Komuso Khronicles
Shakuhachi Store and Workshop: Tai Hei Shakuhachi