For anyone else who stumbles upon this thread, it is worth pointing out that this problem has now been solved without requiring a hacked solution.
From the evidence I've seen, the problem affected all Mac models with Intel GMA X3100 or NVIDIA GeForce 8000 series graphics chipsets, including the MacBook (late 2007 or early 2008), MacBook Pro (mid 2007 and early 2008), iMac (early 2008) and Mac Pro with NVIDIA GeForce 8800 card. It started when Mac OS X 10.5.3 was installed, and also affected early 2008 MacBook Pros which came with 10.5.2 but already had the newer drivers.
The specific problem was that those drivers dropped support for selection of 256 colour mode. This affected Starcraft, Diablo II and a few other old games which tried to select that mode.
Blizzard has now released Starcraft 1.15.3, which no longer requires 256 colour mode (so a manually updated Starcraft will work on the affected models).
Apple have released Mac OS X 10.5.5, which reinstates support for 256 colour mode (so older versions of Starcraft and other applications using 256 colour mode will work on 10.5.5 and later).