A wonderful way to help out troops and veterans at a time when they really could benefit from a helping hand and a smiling face is to volunteer at a military hospital or a Veteran's Affairs Hospital.
There are MTF's and VA hospitals across the country, so chances are one is a short drive from your home.
There is a good list of MTF's on the wounded warriors website:
Each will have it's own process for registering to volunteer. Here are the guidelines for Walter Reed Medical Center in Washington, DC
You can register to volunteer in a VA hospital and find one near you at the VA website:
Wherever you help, it will be needed and appreciated.
During seven years of residency at Yale New Haven Hospital, I was in and out of the VA hospital in West Haven. I can recall three New Year's Eves spent watching the midnight fireworks over New Haven Harbor with the veterans on the surgical wards on fourth floor. Most of the vets we treated were WWII troops who were being treated for lung cancer, colon cancer, and diabetic feet. The stories they told were amazing. I would go into their rooms to check the blood pressure in their ankles, and come out an hour later having heard a first person account of the beaches at Normandy. I got far more from them then I ever could have given.