I talked about changing nameservers in my last post (about using add-on domains to save money on hosting). However, what I didn't elaborate on, was what nameservers are, and how you would change them.
Nameservers map the human-friendly domain name (like joyhealey.com) to the physical IP / Internet Protocol address (unique internet address) where your domain is stored. This is done using Domain Name Servers (DNS). To explain DNS, I am quoting from an excellent site HowStuffWorks:
DNS is a protocol within the set of standards for how computers exchange data on the Internet and on many private networks, known as the TCP/IP protocol suite. Its basic job is to turn a user-friendly domain name like “howstuffworks.com” into an Internet Protocol (IP) address like 220.127.116.11 that computers use to identify each other on the network.
So, (for example) you may have registered your domain name with GoDaddy, but be hosting it at Hostgator. You need to tell GoDaddy how to point your domain name to Hostgator's servers, where the files making up your website are being hosted (stored).
You would login to your domain registrar account and from within your account, launch the domain management section. Select the domain name you want to change and you will see information such as this below (from GoDaddy, where some of my domains are registered).
Select the drop down option to “Set Name-servers” and change them to the Name-servers of your hosting account. In the example screen above I'm using Hostgator's name-servers NS2295.HOSTGATOR.COM and NS2296.HOSTGATOR.COM.
Your values will almost certainly differ. Ask your hosting company what to use. Or they should be shown on the Control Panel (cpanel).
Having made the change, you need to allow a certain length of time for the new settings to be propagated round the Internet. The time needed is unpredictable. It can be fast, or may even take as long as 48 hours. After a suitable time you should find that you can address your new site from the human-friendly name.
Resist the temptation to raise support tickets or resubmit the change until a suitable time has elapsed. In the former case you'll just be reminded you haven't waited long enough. In the latter case, you'll probably restart the whole “wait” time again.
This is all “stuff” I didn't know when I first started out online, but everyone assumed I knew all about it and treated it as something I could do in 5 minutes. It wasn't! So apologies if this is old-hat to some readers. Hopefully it will be helpful to newer people.
Update October 2019
Some online marketers have expressed concern that Hostgator sites may be slow to load, and in fact I moved all my sites away from Hostgator to DreamHost (affiliate link) for exactly that reason, but I have left this post here because it illustrates the principles involved.
Update August 2022
I have been shown this excellent resource to generate the best domain name for a mobile app or business. Do check it out.