No scripting involved, but just for fun!

You need to create 2 files: ilike.xml and ilike.htm

Content ilike.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<Module>
  <ModulePrefs title="iLike"
  directory_title="iLike"
  description="iframe"
  author="Your Name" author_email="Your E-mail"
  author_link="Your Website"
  scrolling="true"
  category="Facebook">
  </ModulePrefs>
<Content type="url"  href="http://location of ilike.htm"/>
</Module>

Content ilike.htm:

<iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwww.somewebsite.com&amp;layout=box_count&amp;show_faces=false&amp;width=100&amp;action=like&amp;font=tahoma&amp;colorscheme=light&amp;height=65" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:100px; height:65px;" allowTransparency="true"></iframe>

replace www.somewebsite.com with the URL of your own domain.

Put these files outside of your google-site but somewhere where you can reach them.

Now you can add a gadget to your page, just point to the ilike.xml file and you're ready to go!