The FreeRepublic web site uses the default font set by your web browser (where other web sites you visit may set the font size in their code). So, you can change the size of the font that you see here on FreeRepublic. On the latest version of Internet Explorer, for example, you click on Tools, Options, then Content to change the default font size.
Oops, I gave you instructions for Firefox. Internet Explorer is click on View then Text Size.