Asterisk/Skype

Start with getting headless Skype to work, then export the display variable for SipToSis:

export DISPLAY=:0

Download SipToSis (SIP to Skype integration software), unzip and start it:

mkdir /opt/SipToSis
unzip -d /opt/SipToSis /tmp/SipToSis_20110310.zip
cd /opt/SipToSis
chmod +x SipToSis_linux
screen -S SipToSis ./SipToSis_linux

When connecting to the VNC server where headless Skype runs, you'll see the dialogue asking you if you want to allow "Skype4Java" to connect to Skype. Go ahead, click whatever makes sense to you... (that would be "Remember this selection", unless you like to do this everytime you start SipToSis, and of course "Yes")

If you're too slow, you may be unable to click any of the buttons - well, you can click them, but nothing happens. If that's the case, just kill SipToSis, reconnect to the screen (screen -r), kill Skype with CTRL+C and start everything up again, including the VNC server, and be quicker this time.