For the last few months Skype has been crashing every time I tried to start it on my MacBook Pro. There were error messages in the crash log like this

Thread 0 Crashed:
0   <<00000000>>        0xffff07d7 __memcpy + 55 (cpu_capabilities.h:228)
1   ...ickTimeComponents.component      0x991fa700 _SGVideoGetChannelDeviceList + 2069
2   ...ple.CoreServices.CarbonCore      0x90cd0a53 CallComponentFunctionCommon + 513
3   ...ickTimeComponents.component      0x991edb29 _SGVideoComponentDispatch + 123
4   ...ple.CoreServices.CarbonCore      0x90cd0738 CallComponentDispatch + 34

Which led me to think it was something to do with Quicktime and/or video. So it occurred to me that starting iChat and opening the video preview before starting skype might help. It does!