Look in:
<your install location>\Shrapnel Games\The Camo Workshop\WinSPWW2\Game Data\Design\
For
SPWW2-MasterIcon.txt and
Terrain Tiles.txt. These will give you some of the unit and terrain file names.
For editing Look in the SHPEdit folder. Read
!Readme.txt and
Shped050.hlp - both will give you good information.
For soldiers, you should also look at MOBHack and its help file.
If you have
specific questions after you get through all this, post them and someone will usually answer.
Good Luck