The main problem that most of the users face is the low internal memory problem, even though now smartphones comes with an internal storage of 16GB or more, though very less people complains about it but the ones who have the devices with comparatively very less memory are probably the ones you will hear complaining about it very often, but even the 16GB memory runs out if you like to keep your device loaded with apps, games, music, movies and other stuff. But now there is a solution for all the international Galaxy S III users to free up the internal memory.
This method is called as ExtSd2InternalSd, which helps users to efficiently swap the internal and external SD card that allows them to actually use the internal storage only for the apps. This might sound complicated but it is not. You just need to format your SD card to FAT32 from your computer and then flash an update.zip that will do all the stuff that is required of the process and that too by itself. After that you just need to reboot your S III and then your internal memory is your external and your external memory is your internal memory, which means you can have up to 64GB of internal memory while you still got the 16GB of external storage. Check out this thread for this much needed process and all the other tips and download links.
Source: XDA Developers