AWS seems to be okay via this status dashboard. Nothing on the Amazon twitter feed either [2].
[1] http://status.aws.amazon.com/
[2] https://twitter.com/amazon
UPDATE: Site appears to be responding now, but there is a maintenance message. AWS dashboard also shows the following updates:
AWS Management Console: 12:14 PM PDT We are currently experiencing
elevated error rates for the AWS Management Console
Amazon Elastic Compute Cloud (N. Virginia): 12:11 PM PDT We are
investigating increased API error rates and latencies for tagging
related API calls in the US-EAST-1 region.