Apple has officially announced what's in store for the 2011 Worldwide Developers Conference on June 6 in San Francisco. The latest versions of its OS X operating system for the Macintosh, and iOS operating system for the iPhone, iPod touch and iPad will be unveiled, along with a service called iCloud.

OS X Lion brings some of the user interface ideas developed for iOS to the desktop (which is sure to be controversial) and some new features like an OS-level Auto Save and an improved FileVault that offers disk-level encryption. For a preview of some of the new features in Lion, visit Apple's preview page.

Apple's press release coyly refers to iCloud as a "cloud services offering", but it's not much of a secret that at least some part of the offering is a music streaming service/online music locker - an idea which is not at all new ( did it way back in 2000).

Earlier this month, CNET reported that Apple had signed cloud music licensing deals with two of the four major record labels, and had deals with the remaining two majors very near to completion.

iCloud will compete with Google's Music Beta and Amazon's Cloud Drive, which are both run without blessing from the majors, giving Apple a sizeable advantage which should outweigh the fact it was last to market.

Back in April, Om Malik reported that Apple had paid Swedish company Xcerion $4.5 million for the domain. Whether iCloud will replace or supplement MobileMe is anyone's guess.

For more information, visit the Apple Worldwide Developers Conference 2011 website.