Rob,

You will be able to accomplish this through the use of a portal alias and perhaps the help of your shared hosting provider.

The first step is to set up DNS to point to your server's IP address. (e.g. www.yoursite.com points to 111.111.11.1)

The second step is to associate that domain (www.yoursite.com) with your web application. In an environment in which you have control over IIS - you can simply use a host header. You may need to contact your hosting provider or look through their documentation to see how you accomplish this in their environment.

The last step would be to add a portal alias to your primary portal. You can do this from the Host -> Portals page. Just make sure that it matches the name of your domain exactly.

The overall workflow is this: DNS -> Web Server IP -> IIS / Host Header -> Application (DNN) -> DNN loads appropriate portal based on IP address

Hope that helps!

Take care,

Ian