We're continuing to work on the issues currently affecting the Americas region, which are resulting in failed login attempts and service issues. While we've identified the causes and are working to resolve them, we expect our efforts to require an approximate two hours to complete. We expect game services to fully return by approximately 11:45 p.m. PDT. We apologize for the downtime, and appreciate your continued patience.

LINK: http://us.battle.net/d3/en/forum/topic/5149175175?page=1#0
Edited by ejb#1818 on 5/15/2012 9:56 PM PDT