Feed them finely crushed flake food or buy fry food. The finely crushed flake food will be fine, though. Don't overfeed. You don't want to try and clean a tank with lots of tiny babies around that may get sucked up by a gravel cleaner.

congrats!

My female (which was thought to be a boy!)guppy is having babies. She looks to have a pinkish sac of some sort hanging out. Is this part of the birthing process and if so which part??

The yolk sac is what is providing them with nourishment. When it is used up, I would supplement with baby livebearer flake food.