This tool allows you to open BMP (8bit) ONLY, convert them from/to old/new shishi arrangement. And if course it allows you to switch palettes.
Before importing in shishi just load the bitmap and click Null palette.
If you want to copy a palette, just drag & drop the one you want to copy unto.
For more information, read this thread:
Palette Editor can be downloaded here: http://zodiac.ffhacktics.com/Palette_Editor.7z