For some of the sites we work on it makes sense to develop the site on the intended launch domain name. For these situations we provide instructions to clients about how to modify their "local hosts file" to view the site prior to it being live for the whole world.
If you are using a PC or Mac the process is pretty simple although it does require some command line access (gasp!). It can be intimidating to use an non-GUI interface, but if you closely follow the simple steps below, you will be all set in no time.
Please be careful with these steps as you can really mess with your DNS settings on your computer, but if you follow closely you will be able to view your development site easily.