Google Marks Whole Internet Malware
Seems to be fixed now. stopbadware.org was down this morning (which Google partners with to warn of bad sites), and Google defaulted to marking everything as malware, even itself.
UPDATE

UPDATE
Unfortunately (and here's the human error), the URL of '/' was mistakenly checked in as a value to the file and '/' expands to all URLs. -- Google Blog


-Janelle