Godaddy will do DNS for you for a fee.
You register your domain name with godaddy for $9 - $10/year. Then, goto a free DNS site - like afraid.org and setup DNS with them. Once that is done, you will be given a set of name servers to link your domain name to the IP address. Go back to godaddy and plug in the name servers.
Using afraid.org, you can also use port mapping and dynamic dns, if your home ISP gives you a non-static IP address and blocks port 80 incoming traffic.