Implementing DNS on Win2k Server

Here is the skinny.
I have a Win2k Adv. server that I am using Internet sharing for my DSL connection. Now that I have a static IP I want to host my domain. I have IIS 5.0 running and serving pages. The question is, do I need to install DNS in order to host my own domain ? I believe I do, but I would appreciate any input as I don’t want to mess up what’s already working. I’m also planning to install my own mail server in the near future.