LOOP.PHP of TwentyTen - copy in child theme:
 near the top:

<?php if( function_exists('wp_pagenavi') ) : ?>
<div id="nav-above" class="navigation">
<?php wp_pagenavi(); ?>
</div>
<?php else : ?>
 <?php /* Display navigation to next/previous pages when applicable */ ?>
<?php if ( $wp_query->max_num_pages > 1 ) : ?>
    <div id="nav-above" class="navigation">
        <div class="nav-previous"><?php next_posts_link( __( '<span class="meta-nav">&larr;</span> Older posts', 'twentyten' ) ); ?></div>
        <div class="nav-next"><?php previous_posts_link( __( 'Newer posts <span class="meta-nav">&rarr;</span>', 'twentyten' ) ); ?></div>
    </div><!-- #nav-above -->
<?php endif; ?>
<?php endif; //end of if( function_exists() )//  ?>

second part near the bottom:

<?php if( function_exists('wp_pagenavi') ) : ?>
<div id="nav-below" class="navigation">
<?php wp_pagenavi(); ?>
</div>
<?php else : ?><?php /* Display navigation to next/previous pages when applicable */ ?>
<?php if (  $wp_query->max_num_pages > 1 ) : ?>
                <div id="nav-below" class="navigation">
                    <div class="nav-previous"><?php next_posts_link( __( '<span class="meta-nav">&larr;</span> Older posts', 'twentyten' ) ); ?></div>
                    <div class="nav-next"><?php previous_posts_link( __( 'Newer posts <span class="meta-nav">&rarr;</span>', 'twentyten' ) ); ?></div>
                </div><!-- #nav-below -->
<?php endif; ?>
<?php endif; //end of if( function_exists() )//  ?>