I read the following quote in a Planet Quake Q&A about ET: Quake Wars today...
Question from McAfee
We don’t have a date yet, but the work has been going well. Aspyr has started working on the OS X version of the game and they have it running already. Timothee Besset at id Software did a lot of ground work on the Linux platform and this is benefiting the OS X platform. zinx is helping Timothee with the Linux binaries, so we expect to have the Linux dedicated server ready when the game ships.
You can find the Whole Q&A here.