The best utility for this, IMHO, is Kotor Tool (a.k.a. KT) (
http://kotortool.home.comcast.net/index.html) by Fred Tetra.
You MUST have Microsoft's .NET framework installed (it's free). If you don't have .NET framework, you can get it at Microsoft Update.
The .tpc files are in a larger cabinet file with an .erf extension. Just look for the ERF files.
KT will allow you to browse through a tree of files, and will actually allow you to view the .tpc images without extracting them. For the purposes of doing skin mods, always use the textures in the ERF file called (as best as I can remember) "swpc...tpa.erf" The "..tpa", "..tpb", and "..tpc" designations only indicate what resolution the textures are, with "..tpa.erf" being the cabinet containing the high resolution textures. Even if you run the game with medium or low quality textures, your modded textures will be still be used by the game when they're in the Override folder.
To extract a file in KT, double click on it so that it's displayed in the image viewer, then use the "Write" button to write the file. It will write in .tga format. You won't need tpc2tga.
DeeDee