From Aspyr Media:
Provides a Universal Binary for both the Civilization 3 Complete and Play the World applications. Fixes error "Load Error: Error Reading file: Missing Entry in: Game Data\text\PediaIcons.txt" Fixes instances where game would sometimes fail when completing research, giving an error about missing Civilopedia entries or other strange behavior. Fixed sporadic crashes when music cues were being stopped. Music stuttering should be greatly reduced. Custom scenarios (such as the SGOTM at civfanatics.com) are now properly found if placed in "~/Documents/Civilization 3 Complete/Scenarios" (searched first) or "Conquests Game Data/Scenarios" (searched second) Saved files are now compressed. (Autosave files are never compressed, which is the same as the PC version.) When playing fullscreen (as opposed to a window), you may now temporarily leave the game by using either Cmd-H (OSX's hide command) or Cmd-Tab. Clicking on the game icon in the dock (or using Cmd-Tab again) will return you back to where you were. Compatibility fixes for several third-party mods. In particular, the "Rhye's of Civilization" mod now works. As a side effect, network games will not work with previous versions. Multiplayer games between PowerPC Macs running Mac OS X 10.3.x and Intel Macs running Mac OS X 10.4.x may experience difficulties. To avoid these issues, all players should be running Mac OS X 10.4 or later.