Set Up A Minecraft Server From Home - Dynamic DNS with FreeDNS
Here I can show you how to set up a dynamic DNS service so you can assign a free domain name to your server, instead of having to give out your IP address to the players every time it changes.
FreeDNS:
http://freedns.afraid.org/
FreeDNS Update client:
http://www.techknowpro.com/freedns/