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
./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")