This document describes how to run Software Update to obtain the latest patches for Mac OS X.
From the Apple Menu, choose System Preferences.
Click Software Update.
Click Check Now (or Update Now)to have your computer query Apple's servers for any new software. Note: Software Update requires access to the Internet.
If updates for your computer are found, a new window will open displaying the available software. Click Install.
If you are prompted, enter an Admin username and password.
After the updates have finished installing, restart your computer if required.
Repeat these steps to see if more updates are now available. Because some software updates are prerequisites for others, you may need to repeat these steps several times to complete the software update sequence.
Information in this document modified from Apple Support.