I read a detailed paper on how popular web sites perform frame busting. There are web site attacks like clickjacking where the site uses frames to trick users. The attack goes like this. The site uses a frame to make you think that you are running on the real web site. Instead you are seeing the real web site, but are on the hacker's frame. Web sites try to prevent this by detecting whether you are on their site, or in an unscrupulous frame.
Your code can check the domain name. But that can be tricked away as well. You can play some tricks with some overlay HTML elements. However those are not fool proof either. What you really need is some support from the browser. IE8 has defenses against clickjacking. So does Mozilla. But you have to employ these defenses in your code. You also have to have users with the right browsers to take advantage of it. The paper I read recommended that you do some HTML hacks of your own to hide content if your pages are found to be framed.
Use the Requirements Already - I am working on a release at work. Initially we were supposed to replicate some bunch of database tables that the customer had in an old system. We did a ...