Baby Progress 1.0 is a free, simple and very useful program, to take control of the foetus during pregnancy.
It lets you control the age of the foetus in days, weeks and months. You can estimate the birth date, days left until that date, and a graph that shows important information about the pregnancy.
Using Baby Progress 1.0 is very simple. The first time you use it you note down the date of the first day of your last period, and from there it gives you all the information you need.