I've learned that when my SSH session dies, the first thing to do is go to twitter and search for "EC2". People were complaining there within about 60 seconds of the outage starting.
Looks like the entire US-East-1 region had connectivity issues. We're a monitoring company, we're watching this very carefully...there is a write up on our blog:
What's funny is that this is what I find myself doing instinctually when I encounter an outage or high latencies on ANY service or site. Heroku (recent process startup woes), Google Apps (slowdowns, specifically Gmail), Amazon (when its hammered by traffic to big deals), etc etc.
I second the comment above suggesting a "crowdsourced" status app monitoring twitter. Although it's no consolation for service interruptions, it does at least keep you sane knowing the problem is elsewhere.
What does it matter if Twitter goes down? The odds of it happening for an extended time right at the beginning of an EC2 outage are rather small, and even in that worst-case scenario, it doesn't really put us in any worse of a position than we're in now.