I recently got the question: when did you start reading out loud to your children? I remember that when I started reading for Paul, he was more interested in eating the book and in testing the gravity law with it than in the book itself.
Now he is very fanatic about books and stories; although he is obviously not able to read. So, the answer is: start reading with your children as soon as possible; it is never early enough!
The piece of text below comes from the poem Television from Roald Dahl; truly fantastic and to the point:
Oh, books, what books they used to know,
Those children living long ago!
So please, oh please, we beg, we pray,
Go throw your TV set away,
And in its place you can install
A lovely bookshelf on the wall.