Apart from the new MacBook Pros, Apple had more to announce today as it unveiled the first developer preview version of Mac OS X Lion. It was back in October when Mac OS X Lion was first shown to us. Mac OS X Lion is slated for a summer launch, later this year.

Apple today released a developer preview of Mac OS X Lion, which takes some of the best ideas from iPad and brings them back to the Mac for the eighth major release of the world's most advanced operating system. Lion features Mission Control, an innovative new view of everything running on your Mac; Launchpad, a new home for all your Mac apps; full screen apps that use the entire Mac display; and new Multi-Touch gestures. Lion also includes the Mac App Store, the best place to discover, install and automatically update Mac apps. The Lion preview is available to Mac Developer Program members through the Mac App Store today, and the final version of Lion will ship to customers this summer
Philip Schiller, Apple’s senior vice president of Worldwide Product Marketing said:
The iPad has inspired a new generation of innovative features in Lion - Developers are going to love Mission Control and Launchpad, and can now start adding great new Lion features like full screen, gestures, Versions and Auto Save to their own apps
In its press release, Apple also highlights some of the major features that are going to be found in Mac OS X Lion.
a new version of Mail, with an elegant, widescreen layout inspired by the iPad; Conversations, which automatically groups related messages into one easy to read timeline; more powerful search; and support for Microsoft Exchange 2010;
AirDrop, a remarkably simple way to copy files wirelessly from one Mac to another with no setup;
Versions, which automatically saves successive versions of your document as you create it, and gives you an easy way to browse, edit and even revert to previous versions;
Resume, which conveniently brings your apps back exactly how you left them when you restart your Mac or quit and relaunch an app;
Auto Save, which automatically saves your documents as you work;
the all new FileVault, that provides high performance full disk encryption for local and external drives, and the ability to wipe data from your Mac instantaneously; and
Mac OS X Lion Server, which makes setting up a server easier than ever and adds support for managing Mac OS X Lion, iPhone, iPad and iPod touch devices
For the forthcoming update, Apple has also revamped its Mac OS X Lion feature page.