Apple released a new Security Update Yesterday.
I highly recommend you install it if you have Mac OSX 10.4.9.
Be aware of the following:
1) Make a backup before you install this update
2) This update will take a VERY VERY long time to reboot your Mac
3) This update seems to have made my MacBook a lot more stable
If after 20 minutes your Mac has not rebooted, hold down the power button to turn your Mac off, then press the power button again.
You can download the updates by following the links below or going to your blue Apple in the left corner of your screen and choosing Software Update from the menu.
Security Update 2007-005 (for 10.3.9)
Security Update 2007-005 (for 10.4.9 Universal PowerPC/Intel)