Check out the Doha Asian Games website:

http://www.dohaasiangames.org

On the right hand side there's a link to information about volunteering for Doha 2006. Right now they're looking for 21,000 volunteers for the event. A good share of those volunteers are needed throughout the course of the next year so you can get as involved as you want for as long as you want.

According to my friends who are currently volunteers, there are plenty of different roles out there for all age and skill levels.