The following are sites to search when you are needing to find particular book levels:
Scholastic Book Wizard (This can become a widget on your own blog or iGoogle home page for easy access.)
Leveled Book Lists (This site from McCarthy Towne School, last updated 2003.)
First Collections and Collections (Kindergarten to Grade 3 leveled list from Pearson)
Leveled Book List (This is optional Fountas & Pinnell levelled list by level, author, or title.)
Professional Resources
Peterson, s@ Schwartz, L. (2008). Good books matter: how to chooseand use children’s literature to help students grow as readers. Markham, ONT, Canada.
Szymusial, K, Sibberson, F. & Koch,L. (2008). Beyond leveled books: Supporting early and transitionsl readers in grades K-5. Stenhouse Publishers. Portland.