This is a tough question. There's even been web sites going to court, because their site got framed by another site.
The HTML answer to the question, is to add
to every link. This would make your links look like the below example:
<A HREF="main.htm" TARGET="_top">The Main Page</A>
This will make sure, that when a user clicks on a link, he/she will jump out of any possible frames. If the page is not framed, the user will not notice a difference.