**This is not a standalone app, you need to download GO SMS Pro version (Free!) in order to apply this theme. You can check GO SMS Pro out by searching "GO SMS Pro" in the android market.
To apply the theme within GO SMS Pro: Menu->Settings->Appearance Settings->Theme selection.
Please report any bugs that you run into. Feel free to contact me via the email I have provided. Thank you!
~MasterTM - MIUI Go SMS Pro Theme