Here is a rundown of what most likely will be revealed during Monday's keynote:
iOS • Don't expect anything on the new iPhone 5S or iPhone 6, or whatever the next iteration of the popular mobile phone will be. That's probably being saved for the usual fall release.
Today will all be about a new version of the iPhone and iPad operating system, also known as iOS. And it's liable to be a big change from before.
Since the first iPhone debuted six years ago, its operating system has been based on one design philosophy, known as skeuomorphism, in which the look of the interface is based on textured, everyday household objects. For example, the "Game Center" feature is covered with green felt and wood trim, like a playing card table. The "Contacts" template is made to look like a day planner, and the iPhone and iPad clock looks like an old analog face with a ticking second hand. With skeuomorphism, the icons also have had rounded corners, the look of a reflective surface, and a kind of three-dimensional design.
Scott Forstall, the former head of Apple's iOS division, reportedly loved skeuomorphism. But he was fired late last year by Cook for not working well with others. He was replaced by the famous Apple designer Jony Ive, who has been responsible for the clean, minimalist designs of all of Apple's hardware, including the iPod and iPhone. Ive reportedly hates skeuomorophism and is bringing the new iOS 7 to a cleaner, simpler interface design, with flat icons and less color.
Whatever Cook shows off Monday with the new iOS, it will be wildly different, so be prepared. What no one seems to know is what new features will offered. Many believe there will be few, with the main focus on the design. At the very least, there will be more built-in social network intergration, probably something like Flickr included in the "share" button.
Also expect a preview of the new Mac OSX operating system for Apple's computers, including the Macbook Pro and the iMac. One additional feature of note for the new OSX 10.9 is the possible inclusion of the voice assistant Siri to the desktop.
iRadio • For a long time, there has been speculation that Apple would create an all-you-can-eat music service similar to the popular Spotify and Rdio. Now, Google has entered the fray with the recently released Google Play Music All Access service, in which you pay one monthly fee and have instant access to millions of songs digitally.
Recently, it was reported that Apple has made a deal with Warner Music, as well as other music labels, for its own Spotify-like service, which everyone is calling iRadio for now. That suggests the company is close to revealing it.
If Apple steps into this race, it will be a serious competitor as long as it gets the interface right.
Also, Apple might announce some fixes and introduce features for its iCloud cloud-based storage service. The latter has been widely criticized for its shoddy performance.
Hardware • Although there will be no new iPhones or iPads announced, Apple will not let the day pass without revealing refreshes on some of its hardware lines.
Expect faster versions of its Macbook Pro and Macbook Air laptops. That's because they will come with new Intel-based CPUs code named Haswell. Intel introduced the Haswell chip last week, and it is expected to become the new next-generation CPU for most lines of PC laptops. The Haswell's biggest benefit is that it will use less battery power Intel claims up to 50 percent less.
The Macbook Air, Apple's ultra-thin laptop, also could have the new WiFi standard, 802.11ac, built-in for faster wireless, as well as a better front-facing FaceTime camera. What probably won't have yet is the higher-resolution "Retina Display" that the Macbook Pros have. Reports say that Apple hasn't quite tackled the extra battery drain that the Retina Display produces.
Those same upgrades Haswell chip, faster WiFi, and higher-resolution FaceTime camera also are expected to come to the more powerful Macbook Pro laptop. And Apple might even introduce the Macbook Pro in an even thinner form factor.
Perhaps the most welcome announcement Apple could make is if it introduced an updated Mac Pro, the high-end business-class desktop computer that is used by artists, graphics designers, and anyone who needs a lot of power for work.
It's been a few years since Apple has refreshed the Mac Pro, and some in the high-tech world even thought the company might some day drop the line. But many believe this is the year Apple reveals a new design that will be smaller but still expandable.
Google+: +Vincent Horiuchi
Worldwide Developer's Conference
What is it • The annual Apple conference for third-party software and hardware developers to show off their latest products and learn what's new from Apple.
When • Monday through Friday at the Moscone Center in San Francisco.
Expected announcements • New version of iOS for iPhone and iPad, new version of OSX for laptops and desktops, refresh of Macbook Pro laptops, new line of Macbook Air ultra-thin laptop, possibly new music service similar to Spotify.