Answer:
According to the directions that came with my pills: If you start the pill the day of your period then you do not need to use a backup method of birth control at all. If you are a "Sunday starter" then you have to wait 7 days. I know its better to be cautious, but if you could get pregnant within the 1st month, then I think the leaflet would say so. They could get into a lot of trouble for that. If you follow the directions in the leaflet that comes with your birth control then everything is ok!
Remember the pill does not protect you from sexually transmitted infections. Only condoms help prevent the spread of disease.