Android 4.0 brings a polished interface that's more visual, more consistent and more interactive. Hardware buttons are replaced by virtual buttons in phones like Galaxy Nexus and Android 4.0 supports this change, while also allowing users to temporarily hide the buttons. Contextual menus are now displayed consistently at the top of the screen, so it's easier to find them. The menu button has been replaced by a recent apps button that lets you switch to an app you've used recently. This feature was already available in Android, but the new interface uses thumbnails and it looks much better.
Just like in iOS, you can now create folders by dragging one app onto another app. You can also uninstall apps or disable pre-installed apps from the launcher. That's a good news for users because many carriers bundle applications that aren't very useful.
Widgets are now resizable and can include more features, just like a regular app. The standard widgets are more powerful and you'll probably use them more often instead of opening the corresponding apps.
You no longer have to unlock a phone to check the latest notifications, see the album art of the song that's currently playing or open the camera app. You can now respond to incoming calls using text message templates and dismiss individual notifications. There's also Face Unlock, a simple way to unlock a device using facial recognition.
The soft keyboard has been improved and it offers better suggestions. There's a new spell-checker that underlines errors and suggests how you could fix them.
Android's voice input engine lets you dictate a text without having to pause. "Users can speak continously for a prolonged time, even pausing for intervals if needed, and dictate punctuation to create correct sentences. As the voice input engine enters text, it underlines possible dictation errors in gray."
There's a new People app that integrates with Google+ and other social services, an updated calendar app that allows other applications to add events, visual voicemail in the phone app, a camera app that supports continuous focus, zero shutter lag exposure, stabilized image zoom, focus detection and single-motion panorama. The redesigned Gallery app focuses on functionality instead of eye-candy and makes it easier to edit photos and sort albums by time, location, people and tags.
Android finally allows users to take screenshots without installing additional apps. The browser syncs bookmarks with Google Chrome, lets you save pages for offline reading and has an option to change the user agent of the browser so you can go to the desktop version of a page. Android's browser includes V8's Crankshaft update which improves JavaScript performance. "In benchmarks run on a Nexus S device, the Android 4.0 browser showed an improvement of nearly 220% over the Android 2.3 browser in the V8 Benchmark Suite and more than 35% in the SunSpider 9.1 JavaScript Benchmark." The tabs share the interface used for switching to a recent app.
The email app brings better contact auto-completion, templates, integrated menu for accounts and labels, nested subfolders and searching across folders on the server. NFC is now used in Android Beam, a simple way to share contacts, apps, videos with compatible devices. "It's incredibly simple and convenient to use — there's no menu to open, application to launch, or pairing needed. Just touch one Android-powered phone to another, then tap to send."
The reference device for Android 4.0 is Galaxy Nexus, a Samsung smartphone that uses a 4.65" Contour Display (HD Super AMOLED) with a 1280 x 720 resolution, a dual core 1.2GHz processor and has support for LTE or HSPA+, depending on the carrier. The phone will be launched next month in the US, Canada, Europe and Asia. Obviously, you shouldn't expect to be able to update Nexus S or other Android devices to ICS before the Galaxy Nexus launch.
Here's a video that showcases most of the Android ICS features, followed by a Galaxy Nexus ad:
{ via Google Mobile Blog }