http://www.k9web.com/dog-faqs/medical/whelping.html
The above site has wonderful info on Breeding, Whelping & Rearing Puppies! I found this site a few years ago before the whelping of our first litter. I found more help from this site than the books I purchased on breeding! I have two printed off copies that I keep with me while preparing to whelp a litter.