Many countries now lease out the rights to use their extensions globally. The best example of this is the .tv domain which actually belongs to Tuvalu. There are now over 250 TLD's globally, to review a comprehensive listing of these, view: Country Code
A number of new Top Level Domain (TLD) extensions including .biz and .info were also recently released amid a great deal of fanfare. These are usually more expensive to register.
There is the temptation that if your first choice of names isn't available as a .com, to register the name as a .net, .biz or .tv etc. Think carefully before making this decision. Not only might it cost you more, but these extensions do not have the recognition of .com - which is the "Beverly Hills" of domain extensions. One of my biggest mistakes in selecting my domain name was to wait for too long - the .com version was already taken by the time I had gotten around to domain name registration and I had to settle for Taming the Beast.net. Many people now go to the wrong address! Nationalistic pride is great, but remember that the Internet has broken down international barriers. Think of your target audience. If it is only the people within your own country, a country specific domain is fine; but remember that we are still in the growing stages of the real global economy and it's best to go for .com - why limit yourself? Also, some countries such as Australia have very complex requirements for registering a local domain name.
Many people, including ourselves are involved in domain name speculation. While the great domain rush was happening, investors made huge profits in reselling domain names. This boom has now become a bust, never to recover. I would advise not to spend your hard earned money in this area unless you can afford to lose it. The only names with real value are one-word generic English names.
To register a domain name, you need to locate a Registrar. Domain name registrars are commonplace on the Internet, but you need to be very careful who you register your domain through. Bigger is not necessarily better. For example, an very well known International company currently offers domain name registration for US$35 a year. For that price you get lousy customer service, delays and very few "freebies" thrown in. But on the other end of the scale, you can pay as little as $9.95 a year and receive quite the opposite - but anything for under that price, be extremely wary of and read the fine print.
Many people are under the impression that registering a domain name also includes space for hosting your web site. While this can be the case with some package deals, it is important to understand that they are two separate services