My advice would be to get yourself a static IP address. Then learn how to setup BIND on your server.
http://en.wikipedia.org/wiki/BIND
DNS (domain name server) is basicly a software that will take a IP address and resolve to a name (domain.com). So, when you type in domain.com in a browser it will look up the IP for that domain at thier local IP. Then go to that server.
user -> types domain.com -> looks up domain.com at thier isp for the IP -> goes to that IP -> they are at your website with domain.com showing in the address bar.
Now, if you did not know the above then I suggest you go to your local tech book store and get a bunch of books over the set up of a server to help you out. -or- Do a bunch of googling for HOW TO on seting it up.
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