In the fall they will have information on it.
Various organizations sponsor tents. I always get e-mails from Leukemia Lymphoma when they are looking for volunteers.
I am sure if you e-mail Wide World of Sports--they can give you a more definitive answer and perhaps even add you to a notification list.
I recall receiving e-mails about Sept/Oct time frame.
They do have training--but if you are out of town, you can be "waived".
You pick up your volunteer stuff at Expo and then report to your assigned spot on whatever day/time that may be.
We had several on our team volunteer on both days--one who had broke her toe and was unable to run the marathon. She said running would have been easier than the water stops as it was tedious work.
It is fun though--I know for the water stops--you receive a jacket and you also will get a 1-day pass to the parks (with an expiration date). It is non-park hopping--but hey, it's a free ticket!