I tried to Extend Web Application on our WSS 3.0 server and I'm getting 'Service Unavailable' for both new URL and the old/previously working one. (I have done the same process on SharePoint 2010 server - works great).
I've removed the Extended Web Application but same results - old/previously working URL won't load. Getting "Service Unavailable". I've tried rebooting but no difference. This is our production server.