For more background information about the shakuhachi, its history, making, different schools and teachers, 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 shops

Shakuhachi Store and Workshop: Tai Hei Shakuhachi

New Bamboo and Second Hands flutes: Mejiro Japan

A very good flute to start with: Shakuhachi Yuu

I personally love the shakuhachi Yuu to play in nature.
I made a playlist of my videos called Seiyu and the YUU