ONScripter is an opensource cross-platform clone of the NScripter Visual Novel engine. The original ONScripter was written by Opagee the fork that supports the English language is maintained by Haeleth.

After extracting ONScripter to your SD Card you will need to install your game files into a directory under /apps/onscripter/games/. These usually consist of a 0.txt or nscript.dat file and a arc.nsa or arc.sar files. Next edit the games.xml file found in /apps/onscripter. Once the game is added to the games.xml file you can simly launch ONScripter from the HBC and select the game you wish to play.

Changes:

updated to latest svn version of ONScripter-En
Fixed crash when playing mp3 files
added missing default.ttf to the test game

http://wiibrew.org/wiki/ONScripter