I made a combat simulator for GC2, which can be downloaded from my website:
http://www.geocities.com/saber_marionette_cherry/index.html
It’s a bit different from Darth Kryo’s, that I also recommend, and is stickied in the GC2 forums:
http://forums.galciv2.com/?ForumID=346&AID=102778
Specifically, his is a lot cooler, and handles fleets… but only simulates individual battles, with no statistics. Mine only does 1-on-1 combat, but simulates thousands of battles, to quantify relative ship powers. His works in a browser, with no download… Mine requires a download AND Java capabilities (free from Sun, of course). His has a GUI, and mine uses a command line. His uses server CPU cycles, and mine uses client CPU cycles.
So, take your pick :) Nobody has requested fleet combat simulation, and I won’t program something that nobody cares about (considering I won’t be using it again until the 1.1 patch). But if anyone here uses the simulator and wants additional features, feel free to post them, and I’ll do my best.