Login to your account with your domain registrar. There will be a section there where you can change the nameservers.
correct with iBBnet... The Registrar that the domain is held with is where you need to set the DNS (Domain Name Server). Log into your account, ie. say GoDaddy.com if that is where you purchased the domain from... ...once logged in GoDaddy has a "manage domain names" link. You can then select the website name you want to set the DNS for and then it has an icon to click for "nameservers". In the popup window you'll see some fields to put in the information for your hosting account where you want the sites files to be setup on. For example I use HostGator as one of my webhosting services. So inside the fields I put in: NS1071.HOSTGATOR.COM and NS1072.HOSTGATOR.COM in the 2nd DNS box. Once it gets saved in your account area, GoDaddy (or whatever Registrar you use) knows to then send traffic to HostGator to go looking for your site/files. Hope that helps! Jerold