Добавить
        // Back link
        $backlink = $db->super_query( \"SELECT id, title, category, alt_name, flag FROM \" . PREFIX . \"_post WHERE id > \" . $row[\'id\'] . \" AND category = \" . $row[\'category\'] . \" AND approve = 1 ORDER BY date ASC LIMIT 1\" );
        if( $backlink ) {
            if( strlen( $backlink[\'title\'] ) > 75 ) $backlink[\'title\'] = substr( $backlink[\'title\'], 0, 75 ) . \" ...\";
            if( $config[\'allow_alt_url\'] == \"yes\" ) {
                if( $backlink[\'flag\'] and $config[\'seo_type\'] ) {
                    if( $backlink[\'category\'] and $config[\'seo_type\'] == 2 ) {
                        $back_link = $config[\'http_home_url\'] . get_url( $backlink[\'category\'] ) . \"/\" . $backlink[\'id\'] . \"-\" . $backlink[\'alt_name\'] . \".html\";
                    } else {
                        $back_link = $config[\'http_home_url\'] . $backlink[\'id\'] . \"-\" . $backlink[\'alt_name\'] . \".html\";
                    }
                } else {
                    $back_link = $config[\'http_home_url\'] . date( \'Y/m/d/\', $backlink[\'date\'] ) . $backlink[\'alt_name\'] . \".html\";
                }
            } else {
                $back_link = $config[\'http_home_url\'] . \"index.php?newsid=\" . $backlink[\'id\'];
            }
        } else {
            $back_link = \"\";
        }
        
        // Next Link
        $nextlink = $db->super_query( \"SELECT id, title, category, alt_name, flag FROM \" . PREFIX . \"_post WHERE id < \" . $row[\'id\'] . \" AND category = \" . $row[\'category\'] . \" AND approve = 1 ORDER BY date DESC LIMIT 1\" );
        if ( $nextlink ) {
            if( strlen( $nextlink[\'title\'] ) > 75 ) $nextlink[\'title\'] = substr( $nextlink[\'title\'], 0, 75 ) . \" ...\";
            if( $config[\'allow_alt_url\'] == \"yes\" ) {
                if( $nextlink[\'flag\'] and $config[\'seo_type\'] ) {
                    if( $nextlink[\'category\'] and $config[\'seo_type\'] == 2 ) {
                        $next_link = $config[\'http_home_url\'] . get_url( $nextlink[\'category\'] ) . \"/\" . $nextlink[\'id\'] . \"-\" . $nextlink[\'alt_name\'] . \".html\";
                    } else {
                        $next_link = $config[\'http_home_url\'] . $nextlink[\'id\'] . \"-\" . $nextlink[\'alt_name\'] . \".html\";
                    }
                } else {
                    $next_link = $config[\'http_home_url\'] . date( \'Y/m/d/\', $nextlink[\'date\'] ) . $nextlink[\'alt_name\'] . \".html\";
                }
            } else {
                $next_link = $config[\'http_home_url\'] . \"index.php?newsid=\" . $nextlink[\'id\'];
            }
        } else {
            $next_link = \"\";
        }
        // Back and Next Link Template
        $back_link = \"<a href=\"\" . $back_link . \"\">\" . stripslashes( $backlink[\'title\'] ) . \"</a>\";
        $next_link = \"<a href=\"\" . $next_link . \"\">\" . stripslashes( $nextlink[\'title\'] ) . \"</a>\";
        $tpl->set( \'{back-link}\', $back_link );
        $tpl->set( \'{next-link}\', $next_link );
В скине fullstory.tpl в месте, где надо показывать ссылки вставить:
{back-link} - предыдущая новость
{next-link} - следующая новость

Вот и все!