Google has a form to submit suspected malware pages.
http://www.google.com/safebrowsing/report_badware/

It is explained in the Google Online Security Blog.
http://googleonlinesecurity.blogspot.com/2007/11/help-us-fill-in-gaps.html

[ Link fixed – David]

I think it's out since they started warn people about malicious websites..
(http://blogoscoped.com/archive/2006-08-03-n78.html)

But i'm not sure..