The K-8 catalogs use Fountas & Pinnell leveling. Not all books are F&P leveled, and you can search for them by level in the catalog.
We don't have leveled free reading in the library catalog for high school students. The best way to get students to read is to offer them a variety of resources and engage their personal interests in graphic novels, short books, comic books, entertaining nonfiction, etc.
"High interest-low reading level" (hi-lo) books
Designed to fit the needs of older students with low reading levels. We have some of those on the shelf.
Reluctant Readers
Describes kids who don't like to read, for various reasons. Books for these kids can have super-compelling plot lines, tap into traditional interests like sports, teen-drama, or use graphic component to make the text more palatable, like graphic novels or nonfiction with lots of illustrations. We have some of these on the shelf.
Reader's Advisory
Over the past 15 years literature for teens has exploded. In the 90s, about 250 young adult books were published. Today, thousands are published each year. Granted, some of this stuff is formulaic and repetitive (like a lot of adult lit), but a lot of it is wonderful and just as good as the finest adult literature. We should be able to find something for everyone.
Take a look at some of the reader's advisory titles on the shelf to understand the field of YA literature.
Some good sites to help find books for young adult readers
A great place for authoritative information. In addition to student research for papers, you can find supplementary or alternative texts when the standard text doesn't work for a student. Collect good articles and use them again and again.
Can't find what you need? Ask your librarian for recommendations for other databases.
Kids Infobits highlights
Research in Context highlights
Britannica highlights
Grolier highlights