EC2 Static IP Addresses
Normally, EC2 instances that you create using Cloudmin get assigned an IP address randomly. This is suitable for some applications like batch processing, but not so for web, mail or DNS hosting where a fixed IP is needed - even if the instance goes down and has to be replaced.

Fortunately, EC2 allows you to request static addresses that are associated with your account. Each address can be assigned to a single virtual system, and will replace it's dynamically assigned address.

This page lists all static IP addresses owned by your EC2 accounts, and allows you to request a new one. Requesting an address is free, but there are hourly charges for unassigned addresses and for transferring IPs between EC2 instances.