Just create sidebar.php (ex., mod/your_plugin/view/default/your_plugin/sidebar.php)

Then add this in to it:

<?php

?>

<script type="text/javascript"><!--
google_ad_client = "ca-pub-000000000000000000";
google_ad_slot = "00000000000";
google_ad_width = 120;
google_ad_height = 240;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js"&gt;
</script>

Thanks for the answer

Has not understood where sidebar to insert?

In to theme/plugin path

Example for blog:

/mod/blog/view/default/sidebar.php