There is some good advice here for ya.
I have read a lot of new studies about breeding and foaling and try to keep up to date on the issue. Most studies say the best is not to intervene and to watch from a distance unless something is wrong. There was a good article I read recently about being able to tell when something is wrong. I have a friend that breeds and she is stubborn about foaling her mares in a small miniature stall than out in her nice grass paddock. Many studies say that its best to let a mare foal outside rather than inside. But there are many tips out there and great articles/books out there. Your vet might also be able to give you good advice. My mare foaled in May and we really wanted to watch but she was VERY sneaky lol. Oh well she did it all herself and was fine. I just checked on her and the baby early in the morning. Biggest advice I have is to study up on it, for knowledge in important in something as serious as foaling.
I would also have your vets number ready close to her due date and know who is on emergency/after hours duty there. Don't worry too much she has nature on her side to tell her what to do lol! I m sure she'll be fine. Good luck on your foaling. And we always love pictures!!