Adding PHP Code to a Page: Alternate Method for Drupal 7
The Alternate Method (PHP, IFRAMEs, JavaScript) (Drupal 7)
The following method is a little more round-about, but doesn't require as much coding knowledge as the previous method. The main downside is that it may be difficult for someone in the future to figure out where your custom PHP or embed code has been stored, since this is a non-standard and uncommon method.