The world of smartphones and PC from my angle
If you happen to have an Android device which is NOT Asus Google Nexus 7 or Samsung Galaxy I9300 SIII, then you are surely left out on getting the official Jelly Bean (Android 4.1) update. Even though the smart Android developers will manage to port Jelly Bean to your device through AOSP (CyanogenMod) or AOKP based ROMs, the experience wouldn’t still be the same because at the moment the unofficial Jelly Bean ROMs are in alpha stages. Besides that, the battery life of these ported Jelly Bean ROMs is more terrible than their stabilty. So, I suggest that for better performance and battery, you should downgrade from these unofficial ports at the moment and wait for a stable version (at least a beta) to come.
Now what to do if you really need to enjoy the awesome look of Jelly Bean and the extra features that it promises? The answer is simple. Just give your Android device a make over.
For ICS/CM9 ROMs only.
Lets suppose that you already have the official or unofficial ICS (CyanogenMod or AOKP) ROM installed in your phone.
The first thing to do when customizing anything is to change its appearance, especially the background. A nice collection of Jelly Bean wallpapers in HD can be downloaded from here.
2. Boot Animation
The animation played when booting the device is also very important (though not necessary) to give a real look. Fortunately, it is available for any Android device here. All you have to do is use a root file browser, go to phone’s root directory and drop/move the bootanimation.zip file to system/media directory which will replace the current file. But before doing so, do backup the copy of your previous bootanimation.zip file.
3. System UI
Warning: Do this only if you know what you are doing!
The appearance of the System can be changed to look like that of Jelly Bean OS. This customization can be downloaded from here.
4. Google Apps
5. Google Now
A great feature introduced in the Jelly Bean is the enhancement of the Google Search app. You can download the flashable zip (latest M7) from here.