The Total War community's been pretty disappointed with official modding support for the past while, but now The Creative Assembly (developers of the series) have released the complete, unpacked, unaltered raw database XML and XSD files for Empire: Total War and Napoleon: Total War.
In layman's terms, these games are now moddable. The past Total War games have had some cool user-created content, so it'll be interesting to see what'll come out of the modding community for the newer games.
The full data can be grabbed here. Get on it.