Apple hosted its 23rd annual WWDC in San Francisco last week. And in true Apple fashion, it once again wowed the crowd.

WWDC is Apple’s Worldwide Developers Conference, an annual event that gives iOS and Mac developers an in-depth look at the latest and greatest in iOS and OS X.

What did this year’s event have in store?

For starters, the introduction of a new MacBook Pro with a Retina display, revamped MacBook Air and Pro models, more details on the imminent OS X Mountain Lion release, and… (drum roll please)…. a sneak peak of the iOS 6, slated for our Apple-loving enjoyment this Fall.

The lowdown on the iOS 6

Apple confidently claims that the iOS 6 will bring the user experience to the next level by “taking your iPhone, iPad and iPod touch in entirely new directions”. Over at Macstories, they’re saying things like: “Apple is closely listening to its customers” because this sixth major build of the OS is “a direct response to customer’s wish lists”.

Sounds promising. But will the new Apple OS impress the insatiable expectations of fans around the globe? You be the judge:

A more streamlined interface and new features like the swipe down to check for new messages. New separate VIP and Flagged mailboxes will list messages from “important contacts” and other marked emails. Adding photos and videos to email messages is now also easier. And Hosted Exchange 2010 users will be happy to hear that the mail application is easily configured for Active Sync.

Arguably the brightest star of the iOS 6, the new maps app has been entirely rebuilt with vector-based maps. Along with crystal-clear text, smooth, responsive panning and zooming, an elegant interface, turn-by-turn spoken direction, interactive 3D views and a stunning Flyover feature… It looks like finding your way will indeed be more enjoyable. Of course, Siri is also there to help. And speaking of Siri…

Siri now knows more about what interests you (i.e. sports, restaurants and movies). It also now has support for more countries and languages and new iPad compatibility. On the iPad, Siri will have a similar interface to its iPhone counterpart but will only be available through a popover window from the Home button.

Integrated Facebook with a single sign-on is available directly in the iOS Settings app, along with optional preferences for notifications, alerts, and privacy access for apps connected with Facebook.

Apple’s cloud-based temporary photo archival system now boasts support for friends, comments, and notifications. And since shared photo streams work over Wi-Fi and cellular networks, but don’t count against iCloud storage, users can share to their heart’s content. Shared Photo Streams will be viewable on the iOS 6, on a Mac, any modern web browser, and on TV using Apple TV.

This is the big surprise for the iOS 6. Passbook holds all your boarding passes, movie tickets, retail coupons, loyalty cards, etc. It’s also time and location-enabled. When you get to the theater, the ticket pops up on your lock screen with QR codes; just swipe to get your pass. Last-minute airline gate change? The boarding pass updates within the app and instantly lets you know.

Those with a data plan can now make FaceTime calls on 3G or 4G, depending on the device. The unified phone number and Apple ID means that someone can call on the phone with FaceTime using your phone number, and you’ll be able to answer on your iPad or Mac. Unification will carry over to iMessage, too. Apple’s obvious goal is to give users a more cohesive and consistent experience by allowing them to use FaceTime anywhere and on any device.

Now you can decline incoming calls with a text message or set a callback reminder. Or switch on the Do Not Disturb function and suppress all incoming calls, except from can’t-miss contacts like your boss or better half.

Safari accounts for 2/3 of all mobile web traffic and with the iOS 6, users can now upload photos to websites too. Meanwhile, iCloud Tabs will keep track of open pages so that users can start browsing on one device and continue browsing on another. Also, Reading List will save entire webpages, so you can catch up on your reading, even when offline.

New features will make life easier for people with vision, hearing, learning, and mobility disabilities: New iPhone hearing aids, Guided Access to limit an iOS device to one app by disabling the Home button, and restrict touch input on certain areas of the screen. What’s more, VoiceOver, a screen reader for blind and low-vision users, is now integrated with Maps.

A few criticisms

Some developers point out that shortcomings like interapplication communication, multiple IDs and iBook support for OS X still haven’t been fixed with the iOS 6. And others wish they have included GPS radio installed in OS X mobile computers.

As for compatibility…

The iOS 6 is compatible with the three latest iPhone generations (3GS, 4 and 4S) and the iPads 2, 3 and 4. Owners of the original iPod have yet another compelling reason to upgrade.

Other restrictions: Siri is no longer exclusive to the iPhone 4S; now it’s also at work on the iPad 3. The turn-by-turn navigation and the Flyover mode in Maps can be used only on dual-core idevices (iPhone 4S, iPad 2 and iPad 3).