I started reading to mine when they were just under a year old. We got the free ones from Bookstart at 8 months and that spurred me on. Both are now keen readers, even son who took a long time to convince that reading could be fun, despite his being good at it. He now has a reading age 4 yrs above his chronological age according to the tests they do at school.
And of course, it's fun. I love reading to my two and miss some of the gorgeous picture books that they've now grown out of, though my daughter sometimes reads them to her dolls!