OK - so you have the job and you've gone over the tips in my first post.  What now?  What should you teach?  It will vary from school to school, of course, but, below I've listed an overview of what I cover at each grade level:

Kindergarten - book care, how to use shelf markers, how to look for books, nursery rhymes, various authors for this age group (Eric Carle, Bill Martin Jr., Laura Numeroff, Dr. Seuss, etc.)
First Grade - how to find a "just right" book using the 5 finger rule, difference between fiction and nonfiction, how to read spine labels to differentiate between Easy, Fiction, and Nonfiction, fairy tales
Second Grade - reinforce 5 finger rule, letter writing, Caldecott Award, using library catalog to look up books, find Easy and Fiction books in catalog and then locate them on the shelf
Third
Grade - basic introduction to Dewey, find Nonfiction books in the catalog and then locate them on the shelf, almanac skills, basic research using online or print encyclopedias
Fourth Grade - Newbery Award, review using catalog and looking up Easy, Fiction, and Nonfiction books, introduce research skills, outlining, bibliography, research projects to correlate with classroom curriculum
Fifth Grade - review using catalog and looking up Easy, Fiction, and Nonfiction books, also review research skills, outlining, bibliography, research projects to correlate with classroom curriculum
Sixth Grade - review using catalog and looking up Easy, Fiction, and Nonfiction books, also review research skills, outlining, bibliography, research projects to correlate with classroom curriculum

I hope this is helpful.  Later, I will post specific projects that I do with students at various grade levels.  Have fun!