The extremely prolific author, Cynthia Rylant, has an easy reader series, High Rise Private Eyes featuring soft-boiled detectives of the furry variety. There are eight books in the series. They are very dialogue heavy and while they are fun easy readers, I wouldn't necessarily recommend them as a read aloud. Reading dialogue fluently is an important skill for every budding reader to practice, but unless the parent enjoys dramatics, it might not make for the most interesting listening experience. (Although it could be argued that listening to dialogue is important, too. So what do I know?)
Nonetheless, my six year old very much enjoys reading this series on his own. The characters Jack (the "snoop"), and Bunny (the "brains") banter and cajole their way through the city while solving minor crimes, like missing sugar cubes and lost whistles. Various urban locales are represented such as: apartments, parks, diners and high-class hotels. I've always liked G. Brian Karas' illustrative style, and I think your kids will, too.
So, if you have an early reader, check out a couple of these books for him to test drive.
Big Kid says: Mom, I need #7 next.