Teen Buckeye Book Award (Grades 9-12)- Books that have gotten this award are nominated by and voted on by teen only. It is a great place to see what other teens love to read.
YALSA (Young Adult Library Services Association), a branch of The American Library Association- They advocate for young adults. Every year they give awards for books for reluctant readers, books that have special appeal to young adults, best audio books and many others. This is an excellent site to utilize if you need help finding a particularly interesting book for young adults.
Lexile- This is a great site to reference if you would like to search for an item and find out its designated reading level.