Making a IP address active

Hi,

I'm a bit of a novice when it comes up to setting up a website on a server.

Basically I need to set up a virtual host for a website and assign an active IP address to it. I can do the vortual host thing and restart Apache, but I don't know how to set up an IP address and make it an active. I have a feeling it has something to do with the hosts file. This is on a Solaris machine BTW.

Could anyone maybe tell me how?

Would be most grateful.

Thanks in advance

Vickie