Pop-up portfolio

Hi guys,
I have seen this alot and would like to do the same for my portfolio. Basicly Its just a nice pop-up that appears when you click a link, but instead of launching a new window it loads, for example, an image on top of the current page and just knocks back the website page it was launched from… normally by just putting a wash over the top of it and making everthing unclickalbe. Do you know what I mean?! So I was wondering if there is an example FLA or tutorial somewhere of how this is done.
Many thanks.