dns, domains, and Win2k server

I am such a domain admin noob it is not even funny, but I will try to ask this question.... I have a web server that hosts a bunch of web sites (multiple domains on one IP). Now, when I set up the domains in the "forward lookup zones" section I set an alias to www Then I updated the host headers on the site to point to DOMAINNAME.com and www.DOMAINNAME.com both to the same IP and both on port 80. This way if you go http://domainname.com or http://www.domainname.com you get to the same place. What I am wondering is: Is there a wildcard I can use so that anything put before the domain name will resolve to the site. Like if someone browsed to blah.domainname.com they would get to the site without me ever having to add the host header blah? Am I even making sense?