Destineer's Mac publishing arm, MacSoft, has released an update for the Mac version of Halo.
This update (a 3.4MB download) is described as "bringing Mac Halo parity with Halo PC v1.05".
The release follows the recent introduction of an update for the Windows version of the game which aimed to protect players against a security vulnerability in online play. Sadly, that patch locked Mac users out of the Halo servers.
The new update rectifies this, and adds support for the graphics card in G5 systems, the Nvidia 6800 Ultra.