**UPDATE** ACR release candidate 6.3 is available now, so no need to hack your .CR2 Exifdata anymore. The full release should be available soon (I have no reason not to trust the release candidates, they've always been solid in the past) Download Adobe Camera Raw 6.3 (Release Candidate)
Own the new Canon Powershot S95? Me too. Want to start editing the camera's RAW .CR2 files now, while you wait for the official Lightroom & Adobe Camera RAW update to come out that supports it? Well it's easy enough to trick these guys into opening them today, and here's how:
Download & Install ExifTool
On the Mac, Exiftool is a command line tool, but if you don't mess with the terminal, worry not it's as easy as copy+paste & then drag & drop. (ps, don't fear the terminal, it's really not that bad)
After you install Exiftool, launch the Terminal
Then paste this in:
exiftool "-CanonModelID=PowerShot S90"
Then, drag and drop the file (or files) you want onto the terminal window.
Boom, the changes will happen automatically, and a copy will be made of the original RAW file (adding '_original' to the filename) in the same directory.
LR and ACR will now think it is a RAW file from the Powershot S95 and will now be editable in either.
Note: There is more information than anyone should care to ever know available at the ExifTool's page.
*Also , this solution comes courtesy of MamboPics on the Adobe Forums: