Do you want frames or an iframe?
I use a search menu in a frame that submits to the mainframe for display of results. Quite straight forward really, here is the form code from the search frame
<table cellspacing="0" cellpadding="2" border="0">
<form name="search" action="main.php" target="mainframe" method="post" onSubmit="return val_search();">
<tr>
<td><input type="text" name="go_string" size="15" maxlength="40" tabindex="1" title="no selection = display all debts" /></td>
<td><select name="go_field" tabindex="2" title="no selection = display all debts">
<option value="all">- select field -</option>
<option value="track">track</option>
<option value="ref"><?=$client?> ref</option>
<option value="name">name</option>
</select></td>
<td><input type="submit" class="mainoption" name="go_search" value="search" tabindex="3" title="no selection = display all debts" /></td>
</tr>
</form>
The target main.php runs the query and displays diff pages according to the results using includes.
If you don't need to query anything, just to display the page according to the menu item then that would be even easier.