Congrats on your new up coming litter! Since this is also my 1st litter, I went out and looked for books to read, searched and printed out info from the net. Watched a whelping dvd. I took in (and still am) all the advice that has been given to me from the support of YT. Just make sure you have all your items all ready to go. I wish you and your mama all the luck!
A wonderful site that has tons of info is
www.debbiejensen.com
also try googling "yorkie whelping" you will get lots of info