National Education for Assistance Dogs Service, or NEADS, is a Princeton, Massachusetts-based group which trains and provides service dogs to people in need, many of them deaf and disabled veterans.

See this article from a Vermont paper that describes how their "Prison Pups" process works and who benefits.

The dogs are trained in prisons by inmates during the week, providing both a benefit to society and a benefit to the inmates who qualify for the program. On weekends, they go to volunteer homes, where their training continues. That's where you could come in. NEADS is always looking for volunteers to host and train dogs on weekends, as well as for donors to fund their programs. Get more information on the NEADS website.

Another great program they offer enables dogs in training to get used to behaving appropriately in the workplace. The Dog at Your Desk program is for anyone within a one-hour radius of their campus (Cambridge is about 45 minutes from Princeton). Dogs are brought in by trainers, who do some human training with that day's handlers and then leave dogs for the day to socialize and get used to spending the day in an office. They are picked up at the end of the day by NEADS. Check the NEADS website for more information about this program.