When you can't use Key Caps, try...
Reader Gail Goldyne is feeling nostalgic for the days of OS 9. She writes:
I cannot find Key Caps in Utilities or anywhere in Mac OSX 10.4.3. I’m trying to figure out how to do the special characters in specific fonts. The Font Book doesn’t allow me to try the modifier keys.
That’s what they pay me for, Gail. Give this a shot:
Select System Preferences from the Apple menu, click the International preference, choose the Input Menu tab in the resulting International window, enable the Keyboard Viewer option, and also enable the Show Input Menu in Menu Bar option at the bottom of the window. A flag, representing your current keyboard layout (a U.S. or Australian flag, for example) will appear in the Finder’s menubar.
From this menu, choose Show Keyboard Viewer. A smallish window that represents your Mac’s keyboard will appear. When you type characters, their corresponding onscreen characters highlight. To view special characters, simply hold down modifier keys (the Option key, for example) and the onscreen keyboard will show you the special characters that are available when you use that particular modifier key (or combination of modifier keys if you’re holding down more than one).