Do you have more information on this? All I found was the teachers and professors section of the Safari terms of service where it states a teacher may:

• post, for the benefit of your students, up to 2 sections of our books on your university or other school intranet. (Safari chapters are sets of individually viewable sections.) You agree to monitor the usage of this site and agree to take it down if it is being used by other than your students and when your class term is completed.
• reproduce photocopies of up to 2 sections of our books for the benefit of your students. However, if any more material is assigned to your students, they will be required to purchase their own issues.

Are you sure your school is complying with the terms of service? Or maybe the books they list are part of the O'Reilly open books project.

Maybe your school paid for it, but if not they should beware :-)

See also: Legality of posting html versions of a few O'Reilly books on my server.

Have a nice day
All decision is left to your taste

just to be clear... this was my post, this isn't a local mirror or anything, it's directly from o'reilly's site.

when i go to http://safari.oreilly.com it says i'm logged in as: Statewide California Electronic Library Consortium. i can only assume they're doing it by IP or domain name. everyone else here gets the same access.