I might (I am) in the minority in this, but I actually played this game on a PS2 controller, and it felt great. What I'm wondering is, will this game be controller compatible? I'm doubting it, but I still want to know. Invisible War just did not recognize the axises correctly, and I'm wondering if the original will do the same.

Invisible War was an XBox game clumsily ported to PC. This is a PC game from the ground up. Huge difference.

I believe XPadder will work for what you need here. http://xpadder.com

EDIT: Apparently, it's not freeware.

Joy2Key is free and can do the same as Xpadder (although it does have less features).

http://www.electracode.com/4/joy2key/JoyToKey%20English%20Version.htm

The PS2 version of the game was changed a lot to work with the PS2 controller (and yes, it worked great, framerate issues aside, I might also be one of those who enjoyed that version more than the PC version), even with XPadder style software I doubt you'll get a very good experience playing the PC version with a gamepad, unless there are mods that change the UI to work like on the PS2 (Invisible War style inventory slots instead of the CRPG inventory grid, d-pad quickselect and menu screen tabs). Don't forget that you also have to type text manually into the terminals/computers in the PC version, where that was automated on the PS2.

The PC version really isn't meant to be played with a controller.

But if you really want to do that then I suggest trying Pinnacle Game Profiler. It's a lot better than XPadder and only marginally more expensive.

It can be found at http://pinnaclegameprofiler.com/