Setting Host Name in setup

I just purchased OSX Server from the MAS. I'm a rank beginner when it comes to networking and servers and hosts, so please bear with me.

One of the first steps in setting up the server asks me to name my host through (a) local network, (b) private network, or (c) Internet. I understand the difference between local and internet but I'm not sure that I want to transfer a domain name I already own from my remote host to my local server.

In the future I'd like to host my own domain on my home Mac as it's a very low key site with very little usage. I'd like to be able to set it up so users outside my home would have access to various parts over the Internet.

My question is: If I initially set things up locally, is it possible to change it to Internet at a future date if I change my mind?

Bonus question: Is there an Apple or 3rd party book or PDF available that goes into the setup and ongoing administration of OSX Server? I don't like hopping back and forth from one local window to the online Apple documentation.

Thanks friends,

-Tod