This is a good idea. I have been playing with XML and XSLT lately and it is possible to create an application which stores data and formats it into HTML for viewing. Random experimentation and exploration is good, but I need a project to work on. I was thinking of merging this foray into web apps with our game.
For the task of turn tracking it should be possible to create an application which will format the data from an XML in a manner which is very recognizable to the Civilization Player (us). It should be possible to allow for the entry of turn information (including notes, remarks, etc) by the Turn Player as well as the creation of new data (when we build/research things). By creating a new XML file for each turn it should also be possible to view the state of the game during any turn.
I haven't delved into the Civ Game XMLs too deeply yet but have been reading up on it and, for the most part, all the game's 'data' is in there...for the purposes of this app it would just be a matter of pulling out the information we needed for math purposes (building/unit names, hammer requirements, promotions, combat/resource bonuses, difficulty, civics, etc).
At any rate, I'm bored these days and need a project to work on. If there is some interest in helping to tweak this thing and attempt to implement it during the game (as long as it is functional) then I can probably have something for us either before start or quite early on in the game to begin playing around with. I would be really interested to see how a project like this would come out with some of the people we have on this team!