how would I set the default web browser for the root user
Launch this from the terminal:


sudo -u root /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome


It will ask you whether you want to set Google Chrome as your default browser. I assume the same technique works for Firefox and most browsers.

I had the same problem when running Skype as root and it fixed my problem (it opens links in Chrome instead of Safari now).