I'm not entirely sure what all the requirements are. In reviewing what the guidelines were, it appears that any T1, who has been diagnosed for 12 months or longer and is over 12 years, is eligible. In our area, there is a brand new org called Dogs assisting Diabetics (DaD). They are in the process of training puppies right now, therefore the applications aren't even going to be ready until August/September.
The process goes something like this: You apply online. It can take 2-3 months before they get your request. The org works with you on your lifestyle and finds a dog that is a good match for you. These dogs have been trained for seeing eye dogs for the blind. After they find the right dog for you, you are required to go to a 2-4 week training class with the dog so they can learn your scent and essentially be trained how to smell your BG levels. In addition, you will also learn how to work with the dog (commands, how to handle the dog in public, etc). After that, the dog is yours.
As I said, I'm new to this whole thing and the only thing we've done is applied for the dog. I don't know all the details, but this is what I read on the organizations website that we applied through.
You should just google "Diabetic Alert Dogs" in your area and if there are any orgs, they'll come up.