Corsaire, the security consultancy, has released
“Hardening Mac OS X Leopard”
a research paper in PDF format.

“This guide is aimed at users in environments requiring stronger
security controls in their operating system, making full use of the
protection features offered by Mac OS X 10.5,” Daniel Cuthbert of
Corsaire says. “It may also be of use to system administrators
wishing to enforce an organization-wide desktop security policy.”