Here's a little tip that works, no matter what web browser you use. (Safari, Firefox, Camino, OmniWeb, Shiira, etc.)
Just head
here and find the bookmarklet called "Resize Window to Full Screen". Bookmark it, add it to your Bookmarks Bar (or whatever the equivalent in your browser is called) and click it whenever you want a full-screen window.
If, on the other hand, you want to increase the font size, this too can be done, though the location of the option differs from browser to browser.