One thing I will add to what Pa8nt said. After the foal is born it's a good idea to tie up the placenta so the mare or foal does not step on it and pull it out prematurely. Most folks just twist it and double it like an old skein of yarn. A great place to learn more about foaling is Mare Stare (Mare Stare - The Web's Best Choice in Streaming Cam Hosting). It's a bit slow now, but beginning in January you should be able to watch lots of births.

I've video taped some of the births, you can find them here: Cheryl624/Mare Stare - Photobucket - Video and Image Hosting They are all miniatures, majesty is a donkey... But the concept is the same! (I have the owners permissions)