The basic tools required for modding SH3:
Graphics Editing Suite (able to edit/open/save TGA)
Model Editing (Wings/Maya/3ds Max)
Text Editing (notepad Duh!)
Hex Editing (google is your friend)
Pack3D (extraction/repack of Dat files)
Minitweaker (further val/sim etc editing)
That should just about cover the basics and if you need further instruction on how to use these tools, most of what you need is in this forum already.
The most important piece of information is: Work with backup copies of files.
