XDA Senior Member amiblindyet has released an APK file that gives Sprint Galaxy S III owners Emoji support on the MMS app on AOSP-derived ROMs. This is not the first time such support has been given. However, now most common issues are fixed. This includes errors with portrait photos, force closes, and other miscellaneous errors. Some of the other features include:
[FIXED] MMS works
Increased MMS picture size
Dark theme with ICS blue to match AOKP, etc.
To install, simply download and flash the zip that amiblindyet has provided in custom recovery. It has been tested on AOKP Jelly Bean and CM10, and should work on any AOSP ROMs based on those. Given that the US variants of the Galaxy S III can share practically everything, expect this to work—or at least get ported—to the other three variants soon enough. In fact, this may even work on other devices running AOSP-derived Jelly Bean ROMs as well.