Today Apple released OS X Mountain Lion GM (Gold Master) build for developers only. This G.M version is almost equal to the final release of the new version. This G.M release is released to make sure that there are no issues or bugs left in the final build. If there are some, so they can be fixed before the public release of the OS X Mountain Lion. This new version of OS X Mountain Lion 10.8 would be bringing in hundreds of new features for OS X users including the side bar Notification feature, same as of the iOS would also be included in the final release.
We expect the final release of OS X Lion might be done in few days because the G.M version is out, so the final release would be following it some time later this week. The OS X Mountain Lion would be released in the MAC APP Store with an initial launch price of $19.99. Once the final version of OS X Mountain Lion is released, every one could download the final build from the MAC APP Store and enjoy over hundreds of feature in it. All we have to do is to wait for the G.M to be cleared, so we can see the final release of OS X Mountain Lion.