Here's a useful tool for educators and librarians, especially those with big walls, windows, or bulletin boards for displaying art and posters. The web 2.0 tool is called Block Posters. You create a poster by first uploading a picture or image, slice it, download the PDF, then print it. Just decide how many sheets wide you want it.
Check out the Block Posters' Gallery for ideas. How could you use it to promote your school, library promotions like "Banned Books Week" or "Library Card Sign-Up Month" or great art masterpieces? Or just one word, "READ".