Nested Ul li menu help

Well this isn't specific to megamenu, but you could do something like this in your template.php

/**
 * Create the footer mini sitemap from items in the menu.
 *
 * @param $hook
 *   The name of the template being rendered ("block" in this case.)
 */
function theme_build_footer_sitemap(){
  // pull the tree data so we can cull the list if necessary
  $treedata = menu_tree_page_data('primary-links');
  
  //trim the children
  foreach($treedata as $key => $value){
    if($treedata[$key]['below']){
      foreach($treedata[$key]['below'] as $subkey => $subvalue){
        $treedata[$key]['below'][$subkey]['below'] = 0;
      } 
    }
  }
  // TODO
  // make any modifications to the treedata
  // limited each subnav to only 6 items.
  // if more than 6 items, ad a more link to point to the parent menu item
  
  // generate the html markup
  $output = theme('footer_sitemap_mini', $treedata);
  return $output;
}

The tpl file i'm calling above ( $output = theme('footer_sitemap_mini', $treedata);) looks like this

<div id="footer-sitemap-mini">
  <div id="footer-sitemap-mini-primary">
    <?php
   
    foreach($menuTree as $key => $value){
      $link = $value['link'];
     // $links = menu_tree_output($menuItem);
      echo '<div class="footer-sitemap-mini-column"><h3>' . l($link['title'], $link['link_path'], $link['options']) . "</h3>";
     // $output .= '<div class="footer-sitemap-minimenu_tree_output($value['below']);
       if($value['below']){
        //echo theme('footer_sitemap_mini_columns', $value['below']);
        echo  '<ul>';
          foreach($value['below'] as $nestedvalue){
           $nestedlink = $nestedvalue['link'];
           echo '<li>' . l($nestedlink['link_title'], $nestedlink['link_path'], $nestedlink['options']) . '</li>';
           }
        echo '</ul>';
      }
     
     echo '</div>';
     
    }
    
    ?>
  </div>

then reference it in your preprocess function

function theme_preprocess_page(&$vars, $hook) {
  
  $vars['footer_sitemap_mini'] = theme_build_footer_sitemap();
 
}

then in your page.tpl.php (or other template file) you can do

print $footer_sitemap_mini;