Check out some of those status bar 'load' applets. Several of them have a built-in screenshot capability: In addition to show you your current CPU usage, you can click on it and a little menu will pop up - in some of these tools there's a screenshot option. Look for the status bar applet applications, check the description, and see if it mentions screenshot.

I use 'load-applet-run' (if I recall the name correctly), but I'm not sure if it's still available for OS2008. I'm on OS2007.