After updating to Mac OS X 10.3.4 or later, the display's color balance may change with Screen Saver use. It may have a light blue tint, for example. This happens only with the iBook G4 and iBook G4 (Early 2004) models, regardless of whether Screen Saver was manually or automatically engaged.
What can you do when this happens? Open Displays preferences, click Color, then click on the name of your desired color profile (even if it's already selected).
If this keeps happening but you don't want to keep resetting the color profile, set the "Start screen saver" slider to Never in Desktop & Screen Saver preferences. Consider using Energy Saver's display sleep feature instead.
This document will be updated as more information becomes available.