How to have Adsense appear under the first post in Wordpress blog?

Following is what I learned recently on having Adsense codes only appear after the first post in Wordpress blog and nowhere else.

Open the index.php file and search for the following lines:

<!–p if (have_posts()) –>
<!–p $postCount=0;–>
<!–p while (have_posts()) : the_post(); $loopcounter++–>
<!–p $postCount++–>

Add the following above these lines:

<?php
$postnum = 1;
$showadsense1 = 1;
?>

After that search for the following lines in the same index.php file:

<?php if ($loopcounter == 1) { include (TEMPLATEPATH . ‘/ad_middle.php’); } ?>
</div>
*** Take note about this gap ***
<?php endwhile; ?>

Add the following scripts into the gap:

<?php if ($postnum == $showadsense1) {
echo ‘

*** Put your Adsense Script here ***
‘;

} ?>

<?php $postnum++; ?>

By the way, this version of Wordpress I use is Wordpress 2.6.3. Not sure if other version of Wordpress are having the same coding in index.php or not … Anyway, worth a try.