Older versions have required a preload command to be put in the launcher, but under Unity, that's not possible. The menu editor doesn't allow me to edit anything (properties button is useless), and even running the command manually doesn't work:
LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
ERROR: ld.so: object '/usr/lib/libv4l/v4l1compat.so' from LD_PRELOAD cannot be preloaded: ignored.
What DOES work is using Skype's "share my screen" feature to share the Cheese window. Go figure. Is there any other way around this?