Google is giving web masters access to the malicious code it finds in their web pages. If the Google bot detects malicious code when indexing a web page, search results pointing to this page will be tagged with an appropriate warning. Website operators can now use the Webmaster Tools to access detailed information about the affected code and trace a problem more quickly. To do gain access to these tools web masters must first validate their web presence by associating it with a Google account.
Google points out that the presented malicious code can only serve as a starting point for a comprehensive web page or server decontamination process. Removing the suspect code without closing the security hole that allowed it to be injected into a system will probably result in a re-infection.
Another new feature in the Webmaster Tools is “Fetch as Googlebot”, which presents the content of a page the way it is seen by Google. The information available there, for example concerning a page’s ranking and key words, can help web masters optimise and migrate their web pages.
See http://googleonlinesecurity.blogspot.com/2009/10/show-me-malware.html
original post: Google highlights malicious code