It looks like Google is seriously broken, all across the board. This began on 2009/01/31, sometime between 0600 PST and 0640 PST.
All search results on Google are returning “This site may harm your computer”. Every search result from http://www.google.com points you to their interstitial URL redirector, e.g.:
Clearing one’s DNS cache does not fix this problem. I’ve verified its not my own connection either, by using lynx and telnet from co-located servers across the United States. This is indeed a Google problem.
I’ll be interested to see what the media makes of this, because this is a pretty severe outage.
EDIT: The outage appears over as of approximately 0710 PST. An hour to mitigate is pretty quick, but an hour of search results broken… ouch.