Try this:
http://msdn.microsoft.com/workshop/author/dhtml/reference/methods/createpopup.asp
Those suckers work over frame boundaries, window boundaries, etc. Just get a popup object and write to its document. Keep in mind that it doesn't share the stylesheets and script functions of the parent window and hyperlinks won't work directly. You'll need to navigate using a reference to the parent window.
var popup = window.createPopup();
var pd = popup.document;
pd.body.write("put entire html document here!");
pd.MenuStuff = new Object();
pd.MenuStuff.BrowserWindow = window;
popup.show(x, y, width, height, event.srcElement);
I've managed to tweak one using CSS to look just like the standard Windows menus.
