For those who haven't already noticed, Apple has rolled out a new version of their already optimized operating system with a slew of small fixes including increased AirPort reliability, Time Machine/Time Capsule updates, and improved Spaces usability.
For those new to Apple's interface, updating is a breeze. Simply go to your Apple icon up top and select the drop down menu "Software update." The rest should be self explanatory. However, if you are still confused, see Apple's FAQ for further images on how to upgrade your operating system.