Once again my weaponry has not arrived. But that's what I get for going with free shipping, I suppose. My football coach quit today, so I am in a good mood! I wanted to discuss now why the Eagles could not carry Frodo and everyone to Mount Doom. Obviously they could have, but the quest was supposed to be kept as secret as possible. Sauron and Sauroman have a vast network of spies throughout the lands, and a huge eagle would be easily spotted. Also, even though they seemed invincible in the movies, they are extremely vulnerable to arrows. It was not risk them dying.
One last reason is that J.R.R Tolkien wrote made these books adventurous! How boring would it have been if birds flew to Mordor in like two days as opposed to almost a year? As stated in Family Guy, "That's not what it's about Chris, it's about the quest." :)