Here is a great website that has a ton of information on the whelping process and what to expect.
Canine Reproduction Video and Book on Breeding and Whelping dogs by Debbie Jensen for dog breeders and Whelping Supplies needed to deliver puppies.
For her whelping box you will want it to be softy and comfy for her but easy to clean out as it will get messy.
I use a plastic storage container that goes under the bed for a whelping box. During whelping I put a lot of sheets in it. After she has had all the pups I put the sheets in the washer, clean it out real quick and replace it with a thick comforter. Just make sure that there is no way the pups can get under the covers.
You will also need a heating pad or heating source to keep the pups warm.
I use a snuggle safe disk, you put in in the microwave for a few minutes and it keeps them warm for hours. Just make sure there is either a cover on it or a blanket over so they don't get burnt.
Here is a link to an online store that carries it...
Dog Supplies, Dog Beds, Toys & Treats Supplies Search - Dog.com
Make sure you have your vet's number on hand.
Here are some supplies you may want to have on hand:
Whelping box
Heating source
Blankets
Towels to clean puppies off
Scissors for cutting the cord, they should be dull
Dental floss or hemostats for clamping the cord
Milk replacers (in case mom's milk doesn't come in)
Nose aspirator
Nutridrops (can be giving to mom during delivery to keep energy up and also given to newborn pups to give them a boost)
Stethoscope (to listen for heartbeats to see whether mom is done or not)
Scale (to weigh pups to make sure they are gaining weight, you will need one that weighs in ounces.)
Thermometer (to keep an eye on mom's tempertature before and after delivery)
Benebac gel (can be given to pups and mom)
Make sure mom is on a good quality puppy food and you will want to add some yogurt or cottage cheese to her food AFTER pups are born to help her with her calcium.
I think that covers the basics.
I wish you and your girl luck!!