I saw this last week on the EA site when it came out, but didnt realize that there was so much information about the mod tools that DICE is creating for BF2. DICEs Battlefield Mod Coordinator Lawrence Brown (Formerly of Trauma Studios) has put together a quick introduction to the mod tools. What seems like it will be the greatest improvement is that it is an all in one package for mapping and modding existing objects. New models and animations will still need to be done in a 3rd party software such as 3DMax or Maya, but everything else can apparently be accomplished in the different subsections of the modding program.
You can read all of the details in the February 4, 2005 Community Update.