How do I connect a domain name to a static IP address?

I’ve got a Mac OS X server connected to a static IP address. I can access the address from anywhere, which tells me it’s working right. But I want to point a domain name to it. I’ve tried to wrap my head around DNS and all that, but am at a loss for where to start or how to proceed. Oh, and I don’t want to do a redirect… It’s gotta be the real deal.