In DNS, for the "domain.com" zone, create an "A" record (excluding a
hostname) and set it for whatever IP you need it assigned to. Then, in the
same zone, create a "CNAME" record that points the "www" hostname to
"domain.com". That's it. Nothing needs to be done in your reverse-lookup
zone (someone mentioned something about it earlier).
It doesn't matter how you have IIS set up (as far as a name/description
goes)--IIS "webs" are based on IP address by default anyway.