Mac OS X security guides
There is some nice documentation released for all people who want to ‘harden’ their Mac OS X installation. Apple released its own document to make Leopard (Mac OS X 10.5) more secure. You can find the guide from Apple here. A few days earlier the center for internet security released its own guide. It contains detailed instructions for implementing the steps necessary for CIS Level-I & 2 security on Mac OS X 10.5 (Leopard). The guide from CIS can be downloaded through here (crappy registration required).