Few of us ever REALLY want Caps Lock turned on; when we do hit it, we do so accidentally. There are workarounds.
You can just disable the key entirely, of course. To do so, go to System Preferences, and choose Keyboard. Then click the Modifier Keys button at the lower right of the Keyboard tab. Finally, set Caps Lock to No Action (or, alternatively, have it pull side duty as a bonus Control, Option, or Command key).
That's a great solution for those of us who only ever trigger Caps Lock unintentionally. But what about folks who genuinely want the option to quickly enter a mode for NONSTOP CAPITALIZATION, yet still want to avoid entertaining said mode accidentally? For those troubled typists, the solution is a free utility called CapSee. It displays an unmissable on-screen indicator when you're in Caps Lock mode. ISN'T THAT GREAT?
Mac OS X Hints