Call me crazy, but it doesn’t seem like you can “natively” lock your screen on a Mac like you can on Windows. Very odd and annoying as it’s something I do everytime I leave my workstation, I’ve even had to agree to a policy that I will never leave my workstation open as I have secure access to production servers (via ssh).
I found some craziness on google where users setup “hot corners” with mouse gestures with the idea that when you “drag your cursor” into that corner the screensaver will be activated requiring a password to get back to the desktop.
You’re joking right?
I can just imagine how many times a day I’d accidentally activate this, especially using dual monitors.
Here is a cool utility I found to get around this apparent shortcoming without silly workarounds, it’s called Utility Lock.
Utility Lock (formerly known as SleepLock) is a custom built Screen Locking mechanism, it was designed after the Apple lock that is available in Apple Remote Desktop, its purpose is to allow for a greater customization in how the screen is locked, you can now have it locked on Sleep/Idle/Intervals and with the AppleScript support you can combine it with other applications like WiFiScriptor.
Nice and simple :)