Announcement: Amazon EC2 Release: Introducing Elastic IP Addresses, Availability Zones, and new public AMIs/Kernels

Elastic IP Addresses are static IP addresses designed for dynamic cloud computing, and now make it easy to host web sites, web services and other online applications in Amazon EC2. Elastic IP addresses are associated with your AWS account, not with your instances, and can be programmatically mapped to any of your instances. This allows you to easily recover from instance and other failures while presenting your users with a static IP address.

http://developer.amazonwebservices.com/connect/ann.jspa?annID=295

This is really good news for servware app vendors - it is becoming easier and easier to design an entire infrastructure around Amazon services.