I meant to add Luka's birthday tracker here for a long time now - and finally here it is!
It is a very cute little application from Lilypie. I found about it when I was pregnant, from a friend who was also pregnant and counting days to delivery. Actually, I believe that's how Lilypie originally started. Now they added counters for children's birthdays, anniversaries, even vacations.
This year, we are counting down to his second birthday (where did the first one go?).