If you did any searching this morning you may have run into oddly ubiquitous “This site may harm your computer” warnings. I don’t work directly on the anti-malware efforts, but I’m sure everyone on the larger search quality team feels the same, sorry for the inconvenience.
You can read more about what happened on the official Google Blog.
Now, if your site is still showing up with “may harm your computer” warnings, it probably because you have actually been compromised. It’s not always obvious – look for hidden iframes and other inserted code.