There really hasn't been a delay though. They said from the start that the 3G's would be 30 days after the wi-fi, so if they come out on the 24th, then they will actually be early!
I did find out that my credit card will send me an email when the balance goes over a set amount, so I set that up. I figure that Apple will charge my cc before they change the status on the site, so that will probably be my first clue that something is happening.
It won't be long now!