You might not know that we put together a set of resources about network security for libraries. The pages are available on Infopeople's website at /howto/security?destination=howto/security . The pages cover both desktop and network issues and provide guidelines for developing security policies appropriate for your library.
One visitor to our site loved the webpages but really wanted all the files in one file. So we accommodated his request. Now the Library Computer and Network Security pages are available in one PDF file !