- System Preferences ? Security ? General ? Check Require password after sleep or screensaver begins.
- Keyboard Shrtcut: Shift+Ctrl+Eject?
[Lifehacker: Lock Your Mac in a Keystroke - Keyboard Shortcuts]
Fresh Mac And iPhone Apps for Mac Fanboys And Fangirls
[Lifehacker: Lock Your Mac in a Keystroke - Keyboard Shortcuts]