International Shakuhachi Festivals are rare. Two have happened in the last five years.

The recent one in Sydney, Australia, 2008, was curated by Riley Lee.
http://www.worldshakuhachifestival08.com/

I participated in the Big Apple Shakuhachi Festival in 2004, curated by Ronnie Seldin
http://www.bigappleshak.com/bas/festivalhighlights.html

I hear the next one will be in Kyoto in 2012.