How to call different different menus at same page in WordPress?

I am using WordPress 3.0.4. I have created approximate 10 page through admin from

Dashboard->Pages->Add New->Update

After that I have created two menu from Dashboard->Appearance->Menu->

The first menu name is header-top-navigation. Second menu name is header-bottom-navigation

After that check the page and add to menu which I need in top header (header-top-navigation) and other pages added to (header-bottom-navigation).

How to call these different menu on frontend?

Use wp_nav_menu() in your theme files.
To insert the menu header-top-navigation

<?php wp_nav_menu( array('menu' => 'header-top-navigation' )); ?>