Confirmation box to accept terms before accessing page on my site

Hi,

I have a directory and I would like a 'confirmation box' (containing the agreement) to appear on the directory homepage that prevents the user going further without first clicking an accept button. Is there a plugin that would allow this?
If there is - would the plugin also cause the confirmation box to appear if the person goes directly to a subpage within the directory without first going through the homepage?

Thanks for the help!
David