Here’s some good news for Amazon’s EC2 users:EC2 now supports Static IP addresses using Amazon’s Elastic IP Addresses feature. Each account can allocate up to 5 Elastic IP addresses to be used (you can contact Amazon to get more). These IP’s can be allocated to one instance which will replace the dynamic IP for that instance - you can move the IP to a new instance at any time.

Beware that an unused IP address costs $0.01 per hour of non-use, which means that while the IP address is assigned to a running instance, you don’t have to pay the charge, but if you shutdown the instance which the IP is assigned to, and don’t immediately assign it to another instance, you’ll end up paying for this charge.

The Elastic IP Addresses feature gives you more control of the IP addresses associated with your EC2 instances. Using this new feature, you use the AllocateAddress function to associate an IP address with your AWS account. Once allocated, the address remains attached to your account until released via the ReleaseAddress function.Separately, you can then point the address at any of your running EC2 instances using the AssociateAddress function.The association remains in place as long as the instance is running, or until you remove it with the DisassociateAddress function.Finally, the DescribeAddresses function will provide you with information about the IP addresses attached to your account and how they are mapped to your instances. Accounts can allocate up to 5 IP addresses top start; you can ask for more if you really need them.

Read about Elastic IP Addresses and other new features over at : http://aws.typepad.com/aws/2008/03/new-ec2-feature.html