So long as the domains have all been set up on IIS, you simply point them all to the root of the same DNN isntallation. DNN uses what it calls aliases to split the domains into the various portals.

When you create a new portal for the domain http//:wimplebottom.com you insert the alias wimplebottom.com into the site settings.

You can also create new portals as if they were in subfolders of anotherdomain and also use subdomains as aliases e.g.

• wimplebottom.com/ningnongs
  or
• ningnongs.wimplebottom.com

There's a lot more to running multiple portals (and even a single portal) than that, but wait until you get to those bridges beore crossing them.

Rob