I don't have any, but I highly recommend the following series:

• Geronimo Stilton
• Magic Tree House
• Time Warp Trio
• the Magic School Bus *chapter* books

Non-fiction in his interests

...that's all I can think of at 6 a.m. on a Saturday!  If I think of more, I'll re-post!

My son enjoyed the Horrible Harry series, and the Wally McDougal books.

Agree with those listed previously ...and would also add : Junie B. Jones, Cam Jansen, Arthur (Chapter book series)

I was going to recommend the Magic Treehouse series as well.

Also Secrets of Droon are at the same level as Magic Treehouse.

I realize this forum is old. I just got on the site and saw the homeschool threads. I do have some suggestions for you though. I'm an elementary teacher who now homeschools 6 kids. I don't know if you're interested in Christian or Non-Christian books so I've listed a mixture of both.

Good beginning chapter books:
 - Magic Tree House - you can find audio books to go with this so they are reading more even before they can do it independently. AND, this site: http://www.mce.k12tn.net/units/units_with_books.htm has comprehension questions for a lot of the books. Some of them can even be done online. I've used it A LOT with my students
 - Three Cousins Detective Club by Elspeth Campbell Murphy
 - Imagination Station books by Focus on the Family - these are new and really awesome. They're like Magic Tree House but from a Christian perspective. I can't wait to see what all they do with this series!
 - Sideways stories from Wayside school - also has audio books available that go with it
 - Hank the Cowdog - more advanced, but also has audio books in existence that can go with them. Kids really like these! I have comprehension questions written for the chapters of the first two books in the series. I'd be glad to share this with you.
 - Wally McDoogle books by Bill Myers - it's goofy and crazy and drives me nuts but little boys think it's great. It teaches good lessons but is silly enough to hold their attention
 - Geronimo Stilton books - the illustrations in the text itself make it appealing to kids
 - Max Elliot Anderson books - this author prides himself on writing books that boys will want to read - adventure stories and such.
 - Then in my personal opinion - when he gets about 4th grade in his comprehension skills, the best non-Christian chapter book ever written is The Pushcart War by Jean Merril. It's just so much fun!! It's a favorite of mine :-)
 - Sugar Creek Gang books by Paul Hutchens - all about little boys roaming around the woods getting into mischief

As you child grows, I have a website devoted entirely to book reviews of Christian Teen Fiction if you're interested. My goal is to review every one that exists and someday get it into a searchable online database. The site is: www.ctfdevourer.com

Hope something in here was helpful!

~ J:-)mi, aka CTF Devourer

I have a few young reader books.  2 Cor. 12:9