In the USA generally, it's from May 15-June 15 of each year. (from TSA-USA).
http://www.tsa-usa.org/
http://www.tsa-usa.org/aChapters/tsachp.htm


Here's Missouri TSA - http://missouritsa.org/?s=TS+Awareness
That's from their main site which is http://missouritsa.org/


I notice some State chapters have their own days or weeks as well. New Jersey for example also has Tourette Syndrome Awareness Week: New Jersey- April 23-29, 2012.


In Australia it's the 6th to the 12th of May in 2012.