As the matter of fact... there is. You have a few options (based on if you just want a better AI or a whole slew of new things).
Go to the CTP2 entrance page, (or from here) go to the files page.
Now if you just want a better AI, scroll down until you find the "AI Diplomacy Mod - Final" by Dale. Download the zip and unzip to your Call to Power 2 directory.
It does not say that you need the Modswapper program to run the new AI... but I think that you might (Dale? or anyone... can you answer this?). You can download the Modswapper zip file from here. Then unzip it and run the setup program.
If you want something more interesting... check out (at least read about) the Cradle of Civilization Mod on the same "files" page. This makes use of a modified (even more aggressive) version of the AI Diplomacy mod. It also adds many other things to the CTP2 experience that make it worth while.