Android 4 is the next OS from Google that will finally unify the smartphone and the tablet versions back into one. Here's a video that shows some parts of it in works.
It should arrive by November from Google with some devices already running it like the Nexus Prime from Samsung. As for the rest of the Android users, well, you know the drill: we're at the mercy of the device makers and carriers. It's anyone's guess when they'll release Android 4 updates for phones currently running version 3.
It looks alright. It's still a bit spartan in some areas but I definitely people will be impressed with the improvements. After the two minutes mark, you'll see the app changes.
Source: Android Community.