How to install Firefox (temporarily) as your default browser:

• Download Firefox from mozilla.com and install as directed.
• Launch Firefox
  
• If it doesn't set itself as the default browser, select the Preferences... item in the Firefox menu.
• In the Main tab, click the Check now button at lower right, and answer Yes to the question pane.
• Reply to the invitation now, and Firefox should handle the problem with the tilted text display.
• If you wish Safari to be your default browser once again:
  
• Launch Safari
• Select menus Safari, Preferences...
  
• In the General tab, select Safari from the choices in the selector on the first line.