Every so often, when I try to go to a site I visit often, I get a Google page with a 404 error message on it, saying it can't find the site. I'm typing the URL of the site I want to visit directly in the address bar. I don't know how it's getting transferred to Google.
It happens using Safari as well as Firefox. Clearing the cache and cookies doesn't make a difference.
I wonder if using Google Public DNS [code.google.com] would cause that? Do you know if you're using their DNS service instead of the one your ISP provides?
I don't think I changed anything at all that would affect my DNS. This morning I was able to connect to the site again. It happens intermittently, and only with that one site. Others I can go to directly without a problem, and 100% of the time.
The Firefox add-on LiveHTTPHeaders (currently for FF < 4.0 only) can show you the status and progress of your requests, showing whether you are being subjected to any redirects along the way. In FF4, the Firebug "Net" tab also shows the same type of header info as LiveHTTPHeaders.
Maybe check the site's Google Safe Browsing Diagnostic page to see if they have been battling malware infections recently that might be causing intermittent redirects to Google.