Last week's mac tip was Google Apps' two-factor authentication provides security boost for Mac and iPhone users which looks at how to setup two-factor authentication on the mac (or anywhere else really, this isn't quite specific to the mac).
Two-factor authentication turns off a lot of people because they think it's too hard but it honestly isn't, and the security benefits it provides are outstanding. Two-factor authentication operates on two principles or components for an authentication "token" (or password for lack of a better term): one thing you know (your password) and one thing you don't (a random time-based PIN that a hardware device generates for you). This means that if someone has my username and password, that information is utterly useless without having my hardware token (which can be, in the case of Google, an iPhone or Android phone, etc.). Which makes my account really quite secure, and certainly more secure than it would be with just a password.
If you sincerely care about your Google Apps security, you really owe it to yourself to check out the two-factor authentication support. It's easy to setup, cheap to setup, and easy to use as well.