Apple releases Mac OS X Leopard Security Guide:

“Apple offers sys-admins almost 250 pages of security best-practices and tips to protect Mac OS X Leopard clients.
Released on Monday, the guide document is a 3.4MB PDF. The guide is aimed at experienced users, Apple says, familiar with the Terminal application and its command-line interface.
Some instructions in this guide are complex, and deviation could cause [...]“

(Via The Apple Core.)