It's been stated (unfortunately) that there will be no mod tools released with the retail version of the game.  There's the possibility for tools to come out with an expansion, much like AP came with a basic map/campaign editor for GC1.

If I remember right, you were yelling pretty loudly telling people there would not be a map editor on previous threads on this subject.

However, with a little bit of inginuity and a good guide to XML nearby, you could probably figure out how to edit the files by hand.  And for the really industrious, if the XML is well documented, it would be a fairly easy matter to build a bare-bones app to generate new files and tweak values.