It is a free program which encourages you to read 1,000 books with your child before he or she starts Kindergarten.
Children from birth through the Summer before they start Kindergarten.
The program is self-paced and you decide how often and how long you will read to your child. It can take anywhere from 3 months to 3+ years.
All of them (provided they have not yet started Kindergarten). Make it even more fun and read as a family!