Research has shown that school librarians and school libraries are instrumental in student achievement, when the collection is resource rich and the librarian is certified and involved in collaborative teaching.
School Libraries Work! is a Research Foundation paper that collects position statements and research findings on the impact school libraries and school librarians have on student achievement. This booklet, in PDF format, is an easy to read and understand summary of the research.
http://www2.scholastic.com/content/collateral_resources/pdf/s/slw3_2008.pdf
Illinois schools participated in a statewide study of school libraries in 2003. The results of that study may be found at
http://islma.org/IllinoisStudy.htm
The Library Research Service provides a one-stop resource to connect with school library research.
Stephen D. Krashen, author of The Power of Reading: Insights from the Research, includes information in his books and website on the importance of providing students with a print rich environment.
On a lighter note, Doug Johnson writes in his Blue Skunk Blog about why he only wants his grandchildren to attends schools with good school libraries.
“Young Learners Need Librarians, Not Just Google” Forbes (Intelligent Investing) by Mark Moran
http://www.forbes.com/2010/03/22/moran-librarian-skills-intelligent-investing-google.html