Jen,

That is great news! There's nothing more rewarding than socializing a mama cat and her babies.

What I would suggest is seeing if the shelter will lend you a cage. It's so much easier keeping them contained as opposed to letting them have the run of the room.

You'll need to work with the mama while she's pregnant. Even if it's just sitting in the room watching tv or reading a book. Your presence will let her know that you aren't a threat to her. Feeding her will reassure her.

Once the babies are old enough (6 weeks) you can start handling them by wrapping a kitten in a towel. Stroke their heads, talk to them. The more handling the better. You'll be surprized how fast kittens come around.

I am so happy for you. Good luck! If I can be of any help, please let me know.