You can always download the most recent version of ACK at Chris’ site:
There you can get ACK for Windows, ACK for OS X, or plain (for Linux or running without the GUI launcher) ACK there.
Also be sure to check out the Jolt Country ACK forum for fan-made patches – ACK user rld has made a series of Mega-Patch releases that add lots of useful enhancements as well as some bug-fixes.
