Aviation Week has a fine overview of the soon-to-be-deployed En Route Automation Modernization system. A brief excerpt:
[The] ERAM system, developed by Lockheed Martin, represents one of the most complex and expensive upgrades the FAA has ever undertaken. ERAM is expected to begin controlling live traffic at the FAA’s Salt Lake City center late this month or early April, and at the Seattle center a few weeks later. Once the system has checked out at these two sites, it will be rolled out nationwide to the remaining 18 en route centers.
While problems remain as the operational date draws closer, they are not atypical at this point in such a large project, stress Lockheed Martin and FAA officials. The $2-billion ERAM effort is on schedule and within budget – something of a rarity for a major FAA modernization project.