Haven't installed the new OS X 10.7 Lion upgrade? Here are step-by-step instructions.
Click on the Apple menu icon at the upper left corner of your screen. Click Software Update.
Software Update will launch, access the Internet, and immediately poll Apple's servers for newly available software.
You'll see this dialog: notifying you there are updates available. Click Show Details.
Here's the list. Read through the description of each one to make sure your 10.7.1 update is the right one. You might need more than one. In my case, I require three updates--for Remote Desktop Client, iTunes, and the Mac OS X Update.
At the License Agreement for each update, click Agree.
The updates will download.
After the download completes, you must do a complete system restart.
When your Mac comes back from the restart, you'll see the update packages installation.
Now log back into your system. Again, click the Apple icon. This time, click About This Mac.
Here you'll see you've got Version 10.7.1. Now you have the latest upgrade to OS X Lion.
You'll be glad you downloaded it. The OS X Lion 10.7.1 update focuses primarily on bug fixes.
For a complete list of changes, check out the Apple Site.