Resgister a domain name

The first thing you need to do when setting up a web site is to register a domain name

A domain is the familiar "something.com" 

Your domain name is a pointer to the actual IP address of your website. 

They're used because they are a lot simpler for people to remember than a bunch of numbers would be. Every website has an IP address, which is a number like 123.456.78.9. The domain name system (aka DNS) translates between those numbered addresses and the corresponding domain names. Each domain on the internet is registered with a central registry handled by a group called InterNIC which is a subsidiary of ICANN - the organization that certifies all domain name registrars. Domain names get filtered through DNS servers, which link the address with the correct domain name. Most websites have a primary and a secondary DNS server - essentially a backup system that increases reliability.

Firstly decide on what you want your site to be before registering your domain. The domain can be anything you want it to be, but it will be more effective if it relates to the subject of your website.
If you're selling shoes, for example, it helps to have a domain name that's related to shoes - all-shoes.com for example. There are some simple guidelines for registering domain names. 

The only characters that can be used in domains are letters, numbers and the hyphen. Domain names can't be longer than 70 characters, but it's best to keep them as short and sweet. They can be upper or lower case, the case of the domain name is ignored by DNS. It often helps to use a combination so they will be easier to read. 

Which is easier to read mywebsite.com or MyWebSite.com? Both are the same as far as DNS servers are concerned. There are several extensions available to use with your domain. The most common by far is .com. It has become synonymous with the internet. Other common extensions are .net and .org. Some of the newer ones are .info, .biz and .name these extensions are not as common and won't be as effective as .com, .net or .org, which people are more familiar with.
There are specialized extensions such as .museum, .aero and .coop which are only available for members of certain organizations. You can also register domains with specific country extensions such as .us (United States) or .de (Germany). The rules for registering country-specific domains vary from country to country, so you need to check with the registrars for a given country to see if you are able to register them.

All domain registrars must be certified by ICANN (the Internet Corporation for Assigned Names and Numbers). There are many registrars with different prices. You can get a full list of all certified registrars at the InterNIC website (www.internic.net/regist.html).

Even though registrars are regulated, they're allowed to offer their registration service through a third party, so most web hosts offer domain registration even if they aren't registrars themselves.

Domains are registered for at least one year and you can buy as many as ten years when registering. A longer registration contract normally gets you a lower price, so if you know you'll be using that domain for some time it can be beneficial to pay for a longer period.