I'm using CS2 and recently upgraded to Mac OSX 10.5.8 from 10.4.11. Camera Raw has never been available to me, but I really need it now because there is no version of Canon's raw file utility (Digital Photo Professional) that will work with 10.5 on a Powerbook G4. The Camera Raw plugin is in it's correct place in Library/Application Support/Adobe/Plut-Ins/CS2/File Formats/Camera Raw.plugin. Neither Camera Raw.plugin 3.6 nor 3.7 works. I am using a Canon 40D. Please help.
Support for Canon 40D was added in ACR 4.2, which works with Photoshop CS3 not CS2. http://www.adobe.com/support/downloads/detail.jsp?ftpID=3730
However you can download and install the latest DNG converter, convert your files using the save options compatible to camera raw 4.1 and later.You will then be able to open your 40D dng files in CS2.
Actually, since he's working on a G4 PPC, I'm not 100% sure the most recent DNG Converter 6.6 will run in PPC. I think he'll need to download DNG Converter 6.5 (the last PPC supported version) HERE. Be sure to download DNG Converter 6.5.