Many local schools now use an online system that allows you to view your child's progress from home:
(Ask your child or his/her teacher for user name and password.)
The following links are also helpful for identifying appropriate books for a child's reading level:
AR BookFinder 
The Lexile Framework evaluates both reading ability and text complexity on the same scale. Unlike other systems, the Lexile Framework uses assessment results to match readers with texts essential for growth and monitor their progress toward standards.