I've put together a recovery-flashable zip of the Jellybean boot animation from the Galaxy Nexus. I've personally tested this on my Galaxy S III and it works beautifully.
1. Download to your phone's SD card
2. Flash in recovery
3. Reboot from recovery.
4. Behold the glory of the Galaxy Nexus boot animation on your Galaxy S III
For those of you who wish to know, the bootanimation is flashed to /data/local rather than /system/media.
To flash manually with Root Explorer, etc. :
1. Download and extract the CWM flashable boot animation file below
2. In the extracted file, navigate to /data/local and copy the bootanimation.zip file
3. Navigate to the root of your SD card
4. Go to /data/local and paste the file there OR alternatively /system/media, overwriting any old boot animation (please backup your old boot animation if you wish to revert soon). Please note that /data/local is the first place that the OS looks for a boot animation. Any boot animation placed in /data/local will override a boot animation placed in /system/media.
5. Reboot and enjoy
This SHOULD work on any device with a 1280x720 resolution. If you flash this on phone other than a Galaxy S III, you do so at your own risk.
Please note: Image in OP is not actual size due to resizing issues. The actual boot animation will appear slightly smaller. Enjoy!