Anyone with the job of administrating a Linux server should take a visit to linuxdoc.org. One free book with is particularly useful is "Securing and Optimizing Linux Red Hat Edition - A Hands on Guide", this is also available in print for those interested.

http://www.linuxdoc.org/LDP/solrhe/Securing-Optimizing-Linux-RH-Edition-v1.3/index.html

Does anybody knows these types of use ful links and books on NT/Win2000 server?

This book in pdf form may also come in handy for the Linux end of things. It's called the Linus Administrators Security Guide.

http://packetstorm.securify.com/linux/admin/lasg-0-1-7.pdf

Regards,

Mike