Hello,
The first thing to do in such cases is to change all your passwords and scan the PC using an updated antivirus and antispyware. Secondly you should check all the site files and see if there is any extra code added there, like iframes related to this attack site. After cleaning all the files you must contact Google via Google webmaster tools or via :
http://www.stopbadware.org/home/reportsearch and request a re-evaluation and delisting. Additionally , you can contact support by emailing
support@lunarpages.com and request a scan for infected files.
After cleaning the site you might be interested on getting some protection for your site using SecureLive :
http://www.lunarpages.com/website-solutions/securelive/Good luck on cleaning your files.

- Marian