Apple today released a developer preview of OS X Mountain Lion, which the company says will be even more like its mobile platform, iOS, than was the last iteration of OS X (Lion).

Mountain Lion introduces Messages, Notes, Reminders and Game Center to the Mac, as well as Notification Center, Share Sheets, Twitter integration and AirPlay Mirroring, all of which were previously reserved for iOS.

Mountain Lion is the first OS X release that was built with iCloud integration. The developer preview of Mountain Lion also introduces Gatekeeper, a security feature that helps keep Macs safe from malicious software by giving the user better control over what apps are installed on your Mac.

Apple now boasts more than 100 million users of iCloud and Mountain Lion aims to make it easier for users to set up iCloud and access documents across your devices. The new system will treat the iCloud like a local disk drive, in very much the way competitive offerings like DropBox work.

The preview release of Mountain Lion is available to Mac Developer Program members starting today. Mac users will be able to upgrade to Mountain Lion from the Mac App Store in late summer 2012.