Google went down sometime around 3pm (EST) for many people. I know it was down for me in New York and if you look at tweets around that time for [google down] you will see hundreds of people saying the same thing.
But it is even neater to use Google's new Twitter Search and if you go to a search on [google down] on there, you will see a massive spike around 3pm to 3:30pm today. Here is a screen capture:
See that spike? Spikes like that do not lie.
Here are some tweets from people reporting Google was down and then up and then down:
Forum discussion at Google Web Search Help.
Update: A day later, Google admitted they were down. Google's Rubie said, "yesterday around 12:00 PST, a small percentage of users had intermittent access to Google that lasted about 20 minutes."
