So, one of my players who was the most vocally opposed to my reasoning, found a piece of info that proved himself wrong. Finally, a definitive answer! It was actually in descriptive text that was giving an example, if I remember correctly. What it came down to was that the readied action was considered to take place during the same turn as the turn in which the action was readied. This shows that you are NOT restricted to just a move or a standard action in your turn. :) Hence, you may not ready a charge.
Based on what I read from some of the replies I received to my initial post, I thought you all might like to see how we resolved this.
I'm really surprised at how many people thought that a charge could still be readied. The rules actually seemed quite crystal clear to me on this issue that charges couldn't be readied. You can't ready a full round action, so you can't ready a charge. Simple as that, or so I thought. ~_^