Thank you for your question regarding your girl you think may be in labor. The onset of labor is best picked up via a drop in body temperature or change in blood progesterone levels several days out from when the puppies are due. If you have not been monitoring either of these and it seems as though your girl is in labor now then you do need to have an idea of what to expect. There are very distinct stages of labor and I would like you to visit and read the info from the following site for details of this as there are quite a number of things you need to know to expect: http://www.2ndchance.info/caninelaborstages.htm
The above link also lists everything you will need for your girl. If you think your girl is definitely in labor, it is very important to have a nice warm area of a lounge or something simliar with several blankets and towels so that she can nest in them - this will be the place for her to settle down in. You will need to keep in touch with your Vet if you notice any ongoing labor problems or if your dog seems distressed during labor as she may well need further assistance or even a C-section!
I hope this is useful to you and I would encourage you to get in touch with your Vet soon to discuss this further. Just reply if I can help you with any further info won't you.
Dr M D Edwards