On Tuesday, Apple made a surprising move and announced more or less exactly what to expect from its Worldwide Developers Conference on Monday.

For a company that tends to keep its cards close to the vest, this is practically an unheard amount of disclosure. Here’s a breakdown of what it’s planning to introduce:

iCloud: The company’s mention of iCloud Tuesday has everyone piecing together the rumors to try to flesh out what it will actually be.

There are a couple of theories. The most popular, of course, is that iCloud will feature iTunes for the cloud — remote access to your music from any computer, and the ability to play and manage your iTunes library from anywhere. Rumors about Apple’s deals with record companies as well as negotiations with television and movie studios, generally point to at least some sort of streaming-media service being included in iCloud.

It’s also likely that iCloud will be a revamped version of Apple’s somewhat disastrous MobileMe service, which currently lets users host documents, e-mail and calendar information for $99 per year. The buggy system has been acknowledged by many, including by Apple CEO Steve Jobs, as a failure.

Lion: Apple’s already given a sneak peek at the next big operating system, which promises to give a much more app-heavy feel to your personal computer.

The system will have a feature called Resume, which will restore your Mac to the way it was when you restart it or quit an application for an update. Another feature called AirDrop will let Mac user transfer files between Macs wirelessly.

Navigation will be based on something called Mission Control, which Apple said unifies its Expose, Dashboard and Spaces features.

The system will also have Launchpad, a menu that shows users all of their apps.

iOS 5: This is the mystery of the bunch. Reports have said that iOS 5 will have a revamped notification system and new widgets, but there’s been little buzz about what’s in store for Apple’s mobile devices.

There have also been reports that, starting with iOS 5, Apple will release updates over the air instead of making users hook up to their computers for updates through iTunes.

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