This was posted by Darrin a few days back to a similar problem.

Put this in your functions.php.

<?php



// function to find location within array



function relative_value_array($array, $current_val = '', $offset = 1) {



    $values = array_values($array);



    $current_val_index = array_search($current_val, $values);



    



    if( isset($values[$current_val_index + $offset]) ) {



        return $values[$current_val_index + $offset];



    }



    return false;



};







// previous page link function



function dbdb_prev_page_link() {



    global $post;







    if ( isset($post->post_parent) && $post->post_parent > 0 ) {



        $children = get_pages('&sort_column=post_date&sort_order=asc&child_of='.$post->post_parent.'&parent='.$post->post_parent);



    };







    // throw the children ids into an array



    foreach( $children as $child ) { $child_id_array[] = $child->ID; }







    $prev_page_id = relative_value_array($child_id_array, $post->ID, -1);







    $output = '';



    if( '' != $prev_page_id ) {



        $output .= '<a href="' . get_page_link($prev_page_id) . '"> &laquo; '. get_the_title($prev_page_id) . '</a>';



    }



    return $output;



};







//next page link function



function dbdb_next_page_link() {



    global $post;







    if ( isset($post->post_parent) && $post->post_parent > 0 ) {



        $children = get_pages('&sort_column=post_date&sort_order=asc&child_of='.$post->post_parent.'&parent='.$post->post_parent);



    };







    // throw the children ids into an array



    foreach( $children as $child ) { $child_id_array[] = $child->ID; }



    



    $next_page_id = relative_value_array($child_id_array, $post->ID, 1);







    $output = '';



    if( '' != $next_page_id ) {



        $output .= '<a href="' . get_page_link($next_page_id) . '">'. get_the_title($next_page_id) . ' &raquo;</a>';



    }



    return $output;



};



?>

Then use this at the bottom of your page.php, or which ever template file you're using.

<div class="navigation">



    <div class="alignleft"><?php previous_post_link('&laquo; %link') ?></div>



    <div class="alignright"><?php next_post_link('%link &raquo;') ?></div>



</div>