It may seem a bit over the top to make a separate section only to point out the existence and location of a patch, however it cannot be stressed enough that the official patch is a mandatory requirement, if you want to get into modding the game.
For the Steam and GoG version of the game this is fairly simple as the respective client will keep your games up-to-date automatically (unless you have deactivated this feature).
For the CD Version you can simply google it or use one of the links below to download it. (Add download links here)
http://www.darksaber.xwaupgrade.com > Star Wars Strategy > Strategy Main Menu > X-Wing: Alliance > Update & Demo > X-Wing Alliance Patch