Apple announced last week that the next release of OS X, dubbed “Mountain Lion,” will be released this summer. Ever lessening the gap between OS X and iOS, Mountain Lion adds a few features and streamlines several others.

One example is iCal, which will be renamed Calendar. Rather than have a To-Do list as part of Calendar, Apple has added Reminders and moved the To-Do list there. Now there is a one-to-one match between where your information is stored on your iPhone and on your Mac. Same goes for Notes; no longer part of Mail, Notes is now its own application similar to how it is in iOS. You don’t have to search for “where did my notes go?” after syncing your data.

Another addition is Messages, which updates iChat to include iMessage functionality. You will be able to chat with iOS users directly using the same program you use to chat with AOL, Jabber, Google, and Yahoo! subscribers. Further, messages will be synchronized across devices, so there’s no more “where was that message with that phone number?”

Game Center has been added to OS X, so you have the same achievements and leader boards as on your iOS device. More Mac game developers are coming up with versions for both platforms, so now you will be able to share your scores between them.

Finally, a sharing feature many have been looking forward to: AirPlay Mirroring. If you have ever used an iPad to share your screen with a second generation Apple TV, Mountain Lion will give you this same feature.

Releasing a new OS so soon after Lion seems to be setting a new trend—is Apple now going to release smaller, annual updates? Instead of releasing a new operating system every two years for $129, perhaps they are now going to update more frequently for $29.99 (but don’t quote me on that). Using the App Store for distribution certainly makes it easier to obtain the software—no more driving to the local store or ordering online and waiting a few days—as well as lessens the environmental footprint.