Once you get registered your domain with the accredited registrar you can’t use the registered domain after registration. It will take time to get activate your domain because there are so many agencies and network involved in the process.
Generally, new domains and changes to domains may take up to [b]5-8 hours[/b] for .COM and .NET domains and for other domain it will take up around [b]24-48 hours[/b] to become effective. This is due to the number of networks involved, and the fact that several different agencies control those networks.
If you book your domain for other countries, it will also take the same time as other domain take it normally. Generally you will get email notification from the registrar to activate the domain.