Edit ---> Preferences ---> Appearance ---> Fonts.
You can set your font-familes to display any font you want on your system. I am using SuSE Linux 8.0, and I got most of the M$ fonts included, so I just checked that "Allow documents to use other fonts" option. That way I get Arial, Impact, etc....the choice of M$ brainwashed "so-called" web-designers who only design their site to render properly on IE, and who don't use style sheets with font-family declarations.