Yes they are, they have the same public access rights as normal SDs except on airplanes (You have to get a special note, not too familiar with that law)

To get a PSD you can look around for places that train them in your area. Most programs require about 5-10 thousand dollars which many will help you fundraise for (May sound expensive, but to care for and train the dog, it's really not) They will interview you and ask about what your disability is and what a dog could be trained to do to help mitigate it. Training takes about two years.