Reports are indicating that the Adobe Photoshop CS3 public beta are due to expire in the coming days at the beginning of May, 2007. One report by Buko, on the Mac Photoshop User to User forum reports that the beta will expire on May 2nd. Other reports claim May 5th (which also happens to be Cinco de Mayo). In any event, rest assured that the beta will expire soon.
For those who still have the Beta installed, Adobe suggests (really emphatically) that you must remove the beta properly before installing the final release version.
On the Mac, the uninstaller is in Applications/Utilities/Adobe Installers. Note: You cannot uninstall by dragging CS3 applications to the trash; instead, you must use the uninstaller.
On Windows XP, uninstall via Add/Remove Programs in the Control Panel.
On Windows Vista, in the Programs section of the Control Panel, select Uninstall a Program.
To aid in the manual removal, Adobe has posted TechNotes regarding how to remove the beta.
Adobe has also posted scripts for the removal of the beta, see: