Resolving Google Safe Browsing Issues
If the following image displays when you visit your website, it's been blacklisted by Google Safe Browsing:
To figure out why this happened, you should visit Google's diagnostic page for your domain at http://www.google.com/safebrowsing/diagnostic?site=[your domain name]
On this page, you can see information such as the current status of your domain, the date it was last visited, details regarding the suspicious content, and instructions for what to do next. You can use this information to assist you in determining how to remove the offending content from your site.
Requesting a Review
The information you see on the diagnostic page might be out of date because Google does not visit every site on the Internet every day. If you've resolved the issues it found, you'll need to request another review using Google Webmaster Tools®, which you can access here.
Google also has a walkthrough containing all of the information you need to resolve a compromised site at google.com/webmasters/hacked/.