Making the keynote address at the Apple Worldwide Developers Conference (WWDC) on Monday at the Moscone Center in San Francisco, CEO Steve Jobs said iOS 5 is a major release, and that it will have more than 200 new features.

Apart from the yet to arrive iPhone 5, the all new iOS 5 will start being seen in devices like iPhone 3GS and 4, iPad and iPad 2, and iPod touch 3 and 4, from this fall. Some dashing features it will have are the new messaging service iMessage, integrated Twitter, PC-free use and a much refined camera.

Apple has envisioned its products to be part of what is essentially the quintessential post-PC era.

We're living in a post-PC world, said Apple iOS chief Scott Forstall at the iOS unveiling. and he said, you can cut the cord, meaning users can now own an iOS device without having a Mac to connect it with, if they wanted.

This has been made possible by taking away many control features from Mac or Windows PC and investing the devices themselves with these features. These include making software updates, creating or deleting calendars or mailboxes.

Here's a quick look at some other major features the iOS 5 will have as Apple is trying to upstage the growth and influence of Android in the smartphone and tablet sphere.

The iOS 5 will feature a new Notifications Center which will collect missed calls, voicemails and text messages. It will also display notifications from the App Store.

Another marvellous feature is Twitter integration for many apps like cameras and photos, YouTube and Maps. This means that from an iOS 5 device users will be able to tweet photos, videos YouTube, locations from Maps etc. All this can be done without using a Twitter App. The 'Twittification' of iOs 5 is so complete that has been set up, this account information will be seamlessly shared by any Twitter-enabled app.

The App Store will bring on to the same platform a bevy of magazines and newspapers which users can subscribe. Most of the major publishers of magazines and many newspapers like National Geographic, Spin, Vanity Fai, The New York Times, Wired, The New Yorker etc., Apple said.

Another feature new on the iOS 5 is tabbed browsing using Safari. This has been brought on to the iOS 5 by integrating the safari Reader feature of the Mac OS X version of Safari.

And, iOS 5 has ensured that Apple devices will now have camera features that will vie with the daunting camera features of its Android Os-based rivals. One new user friendly feature is that there is no need to unlock the phone and navigate away to use camera functions. Now on, users can double click on the home button and proceed by clicking on the camera icon on the lock screen.

And then there area a whole lot of features like crop, rotate, red-eye reduction, and one-click image-enhancement capability as in iPhoto.

And what makeover has been given to the Mail features? New iOS-enabeled devices are set to give fuller mail features. These include options for bold, italic, and underlining, indentation and flagging. A text search through the message has been enabled. You can also drag addresses between fields and enjoy system-wide dictionary.

There have also been some refinements for the Game Center app, and a Reminder app with some interesting and highly useful features. There is also new AirPlay mirroring and automatic background Wi-Fi sync to iTunes.

And then the new iMessage app which adds messaging to iPad and iPod touch, giving encryption features and the flexibility to be sent over 3G and Wi-Fi.