I have a Hercules Webcam - but when I use Skype, it only shows me a black rectangle.
I have run dmesg and it sees the camera OK
[ 1.239505] usb 1-5: New USB device found, idVendor=06f8, idProduct=3003
[ 1.239507] usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 1.239508] usb 1-5: Product: Hercules Dualpix HD Microphone
[ 1.239509] usb 1-5: Manufacturer: Hercules Dualpix HD Webcam

If I run VLC Media Player, it can see the camera.

In Skype, if I go to Tools>Audio&Video it lists the camera as 'Hercules Dualpix HD Microphone'. There appears to be a drop-down, but the microphone is the only option.

Does anyone know what I might do to get skype tgo use the camera instead of the microphone?

Thanks

Sounds like a problem with Skype on Linux rather than the Camera.

Since Skype is a closed sourced Microsoft product, there's very little to do.
But what did your web searches reveal so far?