The combined steps are correct between the question and the comments. You just need to debug each step.
Google "DNS lookup", I usually use www.dnsstuff.com, but pick whichever you like. First check that the name servers are those you entered with your registar, if not, double check you've told your registar to use them, otherwise, just wait longer. If yes, double check them against the values in the Route 53 panel.
Next, check the A record value reported against the one you entered. Ensure you've selected "simple" as the Route 53 routing policy and set "Alias" to No.
If the above two values are correct, ensure your apache server is responding to port 80 and navigate to the IP address of your server in a browser. If that works, one of the above two steps are incorrect (and make sure it's not someone else's stock Apache install), or haven't propagated yet. If it doesn't work, ensure the security group set against that instances allows all IP addresses on port 80 (that's 0.0.0.0/0).
Note on the security group admin interface, after you "add rule", you still have to "apply rule change" before it comes into effect.
If resolving the security group inbound setting it still doesn't work, you either don't have Apache running correctly on port 80, or you have something like iptables applying an internal firewall on the server. Try something like www.yougetsignal.com using the IP address and port 80. If that works, most likely Apache has the problem.
If you continue to have problem at this last stage, run up a stock linux image, just install Apache, use the same security group and check the Apache instance responds using the amazon public DNS of that instance through a browser. If that works and yours still doesn't, you've done something custom to your instance that only you can debug.
If everything is correct on the remote DNS lookup reports, but not locally on your machine, flush the local DNS cache and try again.
