I just thought I would share with everybody this web site, BabyCenter, that I enjoyed (and still do) while I was pregnant with my sons.
I got to watch the progression of the new baby in my belly while also tracking the development of my 5 month old (I had babies back to back by the way - they are 12 months apart in case you didn't know that).
First you set up a login and password, then log your due dates and/or child's current age.
Don't get too caught up with the specific developmental details because every child is different, just keep it light and see/learn what's going on in the belly!
And if you're anything like me, your views are a bit less "traditional" and more alternative when it comes to some baby and pregnancy issues (i.e. diet, routine, medical and lifestyle issues) than the web site discusses. But it's a great site either way because it will send you email alerts that apply to you at your pregnancy stage and/or your child's milestones.