More to explore:

High Wizardry (Young Wizards) by Diane Duane (School & Library Binding)
Song of the Exile by Kiana Davenport (School & Library Binding)
The Middle Moffat by Eleanor Estes (School & Library Binding)
The Wartville Wizard by Don Madden (School & Library Binding)
The Wizard in the Tree by Lloyd Alexander (School & Library Binding)
Where Willy Went by Nicholas Allan (Library Binding)
WHERE WIZARDS STAY UP LATE: The Origins Of The Internet by Katie Hafner (Hardcover)
Where Wizards Stay Up Late: The Origins Of The Internet by Katie Hafner (Paperback)
Wind Says Good Night by Katy Rydell (School & Library Binding)