The portrait view of iPhone shows normal font, but when viewing the site in landscape iPhone makes the font bigger.

Here's a CSS fix for making the font size normal in iPhone landscape view:

@media screen and (max-width: 600px) and (orientation:landscape) {
  /* Adjust font size on landscape. */
  body { -webkit-text-size-adjust: none; }

The "-webkit-text-size-adjust:none", makes the font size normal.

Just putting this in the main style sheet can muck up text re-sizing on desktop browsers though, so it's better to put it in Media Queries.