I am in the process of putting up a simple site for a bunch of old college friends to reconnect (most likely something like a wiki). Having never done ths before, I'm hoping to get things right the first time.

If I register my domain with Company A, and allow their default DNS settings, what happens when I use Company B for hosting the actual site? Do I just tell Company B the name of the domain, and off we go? Do i have to get Company A and Company B to cooperate in some fashion to use Company B's DNS information?

From what I've read, it seems very straightforward, but I'm hoping to avoid any hidden gotchas (hidden to me, anyway).