Searching and Extracting
JEFindRes v0.3a
This tool can search files within all of the game's BIF, MOD and RIM files and the override folder and extract them. JEFindRes allows for simple regular expressions such as "j04_*.dlg" or "*.nss". It also includes Txb2Tga and can convert TXBs upon extraction. (See this post at lucasforums.com for more info)
ERF/MOD/RIM Editor
ERF/MOD/RIM Editor for Jade Empire (with correct file type associations)
See the tutorial about Searching and Extracting Files to get some tips which of these tools is best to use in what situation.
Images
Txb2Tga v0.1a
Converts Bioware's custom image format TXB into the editable TGA.
2DA Files
Convert2da
Standard V2.0 2DA files can be edited and saved with a simple text editor such as notepad. However, not all 2DA files use V2.0, and earlier versions require special tools to be opened and edited. The "players.2da" file in Jade Empire is one such example.
Convert2da allows you to convert V1.0 2DA files to V2.0 so that they can be opened in a simpler fashion.
tk102's Excel Add-in
This add-in allows users of Microsoft Excel to read and write .2DA files using the afore-mentioned program.
KotorTool
Although it was designed for the game bearing its title, the Knights of the Old Republic Tool works just as well for Jade Empire as far as 2DA editing is concerned. Just ignore the error messages at the beginning and use the "Open 2DA Editor" function from the "Tools" drop-down menu in the main window.
GFF Files
K-GFF
Editor for Bioware's GFF (Generic File Format). Nearly half of the game's files are stored in this format.
Dialog
Talked v1.1.1a
Editor for the dialog.tlk
JE DLGEditor v2.3.0a2
Editor for DLG Files
Saves
Jade Empire Savegame Editor v0.6
A basic savegame editor for Jade Empire.
SAC Utils
With these two command line tools you can uncompress your savegames and recompress them when you are done editing them. The resulting files are all SAVs and can be edited with K-GFF. Note that some virus scanners incorrectly flag these tools as malicious. That's a false positive!
Compiler
nwnnsscomp
Compiler for the game's script files. Takes NSS files as input and outputs NCS files. It can also be used to decompile NCS files into more readable PCODE files.
PHP Classes
Additionally there is also a group of PHP classes for reading and manipulating 2das and the dialog.tlk:
(a class for GFFs will soon be added)