LockTight Secures Your Mac With a Hotkey
Mac OS X only: Screen locker utility LockTight adds a shortcut key combination for OS X users to quickly lock your workstation from the keyboard.
Windows users switching to using a Mac might be surprised to find no equivalent to the Winkey+L shortcut combination that locks the screen, especially helpful in work environments or at home to keep little fingers from opening things they shouldn’t.

LockTight plugs into OS X as a simple system preference pane with a configurable hotkey, but for full effect you might want to configure your Mac to require a password when coming back from the screensaver and disable automatic login. Hit the link for the download, or take a look at the Switching to Mac guide for all the steps.
I've ended up using Expose, top right "Start screensaver", and then "require password after X seconds" under the security settings
Works nicely once you train yourself to flick the mouse into the top right
That's indeed a good alternative .. and it doesn't require third party software.
thanks for the info, i'll use it for my mac
Awesome find. I have been looking for a way to do this, as I run a hackintosh version in vmware and love the function on my windows PC. Keeps it safe from prying eyes haha.
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