How can I tell if my MacBook's iSight has a hardware problem? I've got a 2006 13" MacBook (Core Duo; the first ones they produced with an Intel chipset), and the built-in webcam doesn't seem to work anymore.

Here's what my System Profiler shows in the USB tab: 

Which makes me believe there's a hardware problem, or a more fundamental problem with my OS (Snow Leopard 10.6.6).  Before I try reinstalling the OS, are there any ways I can test the functionality of the hardware? I'm willing to open up the computer if needed.

Note: I've already tried resetting the PMU, along with the other steps on Apple's "How to Troubleshoot iSight" page.
If System Profilier isn't showing it up under USB then the iSight has been physically damaged beyond repair (not accepting power) or has been somehow disconnected from the Bus. System Profiler always displays connected devices, even if they're corrupted or non-functioning.

Take your Mac to the Apple Store and they will tell you what it will take to fix it. The most likely scenario is that it will be a free repair, and they'll clean up your computer while they're at it :)

If you can't get to an Apple Store call 1-800-MY-APPLE and ask them about your options.