I'm searching for appropriate books for my six year old to read this summer for the reading program and came up with this Listmania List on Amazon. I love how she broke down the lists by age and grade-level.
For the six year old, the list author says: "Books to fulfil a desire for more complex stories, without bringing in issues that a six year old is not prepared for."
Her list begins with five year olds reading at fifth grade level and ends for eleven year olds reading at a high school level. (And then some.)
Amazon Listmania by "Laura in China"