On OS X, because of Canon's use of a special casing file to identify applications that when choosing application manages color printing, set No Color Correction instead of Color in the printer driver, LR3.2RC needs to be added to the AppColorMatchingInfo.xml file.
This file includes all previous updates.
The file goes here.
Make sure you save the original in case you want to go back to it.
Thank you, thank you, thank you!
Yes, I second the thank you!
Lightroom 3.2 final release has the internal name of Lightroom 3 so it is already listed in the AppColorMatchingInfo.xml. That is if you have installed the x300 drivers or have replaced the AppColorMatchingInfo.xml file with my version.