If you are looking for some Middle Grade (upper Elementary and lower Middle School) books for boys, Michelle Skamene suggests you simply click on over to the Reading Rewards Blog part 1 and Reading Rewards Blog part 2.
For even more suggestions, there's a whole blog dedicated to boys reading over at Guys Read.
The blog for the Charlotte-Mecklenburg library system called Boys Rule Boys Read focuses on boys. As does another blog -- Boys Rock Boys Read. That blog has a column of Most Popular Posts and the first one is Books Every Guy Should Read.
Have fun. -wo