Time to go under your Apple menu and select Software Update.
Yesterday, Apple released a substantial update to Mountain Lion. Mac OS X v10.8.3 Update adds several new features (including the ability to install Windows 8 under Boot Camp, support for 3TB hard drives under Boot Camp, and a new version of Safari) and squashes a few bugs. It’s recommended for all Mountain Lion users.
If you’re interested in details, read all about the update here.