One irritation that people who switch to Mac from Windows find is that there isn’t a quick way to lock your screen. Enter LockTight.
LockTight originated as “SleepTight”, but neither were available for Intel Macs, until Ben Haylock built an Intel compatible version. To install LockTight, download and then uncompress it. Inside the LockTightIntel folder you’ll find two sub-folders – LockTight-0.1 Intel and LockTight-0.1 PPC. Inside the LockTight-0.1 Intel folder (presuming you have an Intel-based Mac), double click LockTight.prefPane.
This will install LockTight as a System Preference. Initially you’ll be presented with a ‘warning’ window, explaining that some combination of Mac models and screensavers can cause serious problems (Note: it also references “SleepTight” in the warning, so I’m not 100% sure this problem applies to LockTight. I tried every default screensaver installed on my Mac, running Leopard, and couldn’t find any problems).
After you click OK to the warning, the settings window for LockTight will open. Make sure that Enable LockTight is checked, and then click the Configure Hot Key button to change the default key-combination of Apple Key+Alt+Shift+L if you wish (I prefer the default, but whatever floats your boat).
If you already have your Mac set to require you to enter your password after the screensaver starts, you’re done. Hit the key-combination that you set to lock your screen, and the screensaver will automatically kick in. Now you can lock your Mac with a simple keyboard-combo.
If you need to set your Mac to require a password to return from the screensaver, return to the main System Preferences window and select Security.
Now you should have both Require password to wake this computer from sleep or screen saver and Disable automatic login checked. Close out of the System Preferences.