I would suggest that you start early - 2-3 months. Short excerpts. Babies are comforted by listening to your voice and very rapidly grasp the connection between the position on your lap, books, visual cues, vocal cues, etc. Continue reading to your child as long as she/he will let you do so. My son and I had bedtime reading until he was 9 yrs. old or so when he wanted to continue his bedtime reading on his own.
Once my son had a fair handle on reading around age 5,(he was an early reader at 4) when he wanted to see a movie, whether on the big or small screen, I would ask that he read the book first if it existed. Then we would see the movie and then we would discuss both after the movie viewing. Because we never had cable tv, movie viewing was special in our family, but reading was a daily event and still is (my son is now 19).