Winex costs 5$ a month, and depending on the version, civ might or might not work. Besides, there are problems regarding the usefulness, as it can prevent ports from being made to linux. Your best bet would be to start with wine, (
www.winehq.com ) as it's completely free, opposed to winex which is a fork from the original wine and kind of proprietary (they don't give back their improvements of the software back to wine). If it doesn't work with wine, then you could try winex, but as I said, it's not perfect. Last, you could run windows in a virtual machine (with a program like vmware) and play civ through windows... However, it's not a great solution unless you have a huge amount of RAM (running two OS at the same time is not really RAM-friendly

)
Oh, and email firaxis to tell them to port, or at least build a client that will let users play civ3 on linux with the original windows games ressources

Or try free alternatives...
www.freeciv.org
P.S. Wine stands for WINE Is Not an Emulator. It's a compatibility layer
