Now that folks are actually starting to get the shipping versions of Adobe CS3 applications, word comes that it's not good enough just to install the new applications over any beta versions you had previously been running. According to John Nack from Adobe, "It's important to run this script (and not just throw the app folder into the trash!), and/or to use the application uninstaller, before installing the shipping version of CS3 apps." The script download page indicates that you must first back up, uninstall the beta with the built-in uninstaller, run the clean script, and finally you can install the new version. I have to say, thumbs down to Adobe for this horribly unMac-like upgrading experience.
The CS3Clean script is a free download from Adobe.