fudzy - 1st rule of html since 1992: NO FRAMES!
You really don't need to use them, and they make navigation using the back keys and refreshing a nightmare for novice users. They are totally fugly and unnecessary.
Rather use a table layout system (2 cols, 1 row) with specified widths, and mock up your first page. The page skeleton should look like this:
CODE
<table width="750" cellpadding="0" cellspacing="0" border="0">
<tr>
<td width="200" style="width: 200px;">
<!-- Your left-hand menu //-->
</td>
<td width="550" style="width: 550px;">
<!-- Your right-hand content //-->
</td>
</tr>
</table>
That should give you a page 750 pixels wide, so its 800x600 friendly.
What u think?
I see you're using ASP. You can make header and footer files from that structure above, and include them in each page you make.