Do you mean that you just want your domain to point to a website hosted at DreamHost? If that's the case, you'll need to point your domain's nameservers to Dreamhost's nameservers: ns1.dreamhost.com, etc.
See this article:
(If your domain registrar isn't listed there, and you can't figure it out in their control panel, you may need to contact them for assistance.)
and this one:
Any questions or problems, just ask.