As you may have guessed from the thread title, this is a patch that decapitalises Pokemon Platinum (US). I decapitalised the entire game as part of an in-progress Platinum hack, and thought I'd share this to save others from suffering through this process themselves. The patch replaces almost all of the horrible ALL CAPS text with capitalised text, as seen in the newer games. This includes the following:
Pokemon names (GARCHOMP becomes Garchomp), both in battle and in NPC text
The start menu
All yes/no boxes
Most other menus
The Pokemon summary screens
I've deliberately left the FIGHT screen and the text selection options capitalised, so you'll need to edit those yourself if desired. Foreign Pokedex entries are also untouched, seeing as they're quite hard to get without the GTS.
The patch is NOT compatible with existing ROM hacks, and is mostly intended to be used at the start of a project before any text is edited, or just to remove the caps lock from a regular play through. While it should be typo free, I can't guarantee it; if you use the patch, please report any mistakes you find in this thread so I can fix them.
The download includes the edited pl_msg.narc file as well as the patch.