Put it in an iframe like this as a custom template called custom_templatename, the link would then be
Code:
http://www.yoursite.com/forum/misc.php?do=page&template=templatename
Code:
$stylevar[htmldoctype]
<html dir="$stylevar[textdirection]" lang="$stylevar[languagecode]">
<head>
$headinclude
<title>$vboptions[bbtitle]</title>
</head>
<body>
$header
$navbar
<!-- Custom Code Start Here -->
<center>
<iframe src="http://www.linktopage.com" width="90%" height="600"></iframe></center>
<!-- / Custom Code Ends here -->
$footer
To make a template go to Styles & Templates/Template manager and under the style you wish to add to click on Add New Template.
Give it a name as per above, paste the code in and replace url to suit your page and site, save.
Add link to Navbar....done, it will be framed in your VB style with header navbar and footer.