No, you don't need FTP, you can do it by editing the theme. In the Wordpress admin screen, click on Design > Theme Editor. Then click on Main Index Template (index.php). You'll probably see something like: <?php if (have_posts()) : while (have_posts()) : the_post(); ?> <h1><?php the_title(); ?></h1> ... Code (markup): Add your adsense code after the "the_title" function - that's the function that draws the page title.
but in my Wordpress admin screen "You need to make this file writable before you can save your changes. See the Codex for more information" i cant modif there. how change that
For that, you need to change write permissions on the template file. If you have shell access to your server, you could just: cd wp-content/themes/YOURTHEME chown apache.apache * chmod 644 * Otherwise you'd have to ask your hosting company to set permissions on those files.