For Writers & Illustrators
The good news is, Chronicle Books accepts unsolicited children's book submission for children of all ages and in a variety of formats. They also accept samples of artwork (don't send in your originals).
The bad news is, they received over a thousand submissions per month, and understandably, will only respond if they are interested in your work. They do accept simultaneous submission, so I would recommend you take advantage of this (otherwise you will be waiting for six months for a response you may never recieve). Click here for the full submission guidelines.
For Parents
Chronicle books publishes such a variety of quality children's books that you are sure to find more than one book in their catalogue that your child will enjoy.
A few recommendations are as follows (click on the pictures to learn more):
"Ivy + Bean" series by Annie Barrows (author) and Sophie Blackall (illustrator).
This is a wonderful series about two very different best friends who never meant to like each other. It is perfect for early readers ages six to eight.