There are two elements that are needed in order to have a live website: 1) the domain name and the 2) web hosting. The two can be provided by the same vendor or by different vendor. We generally recommend that for easier maintenance that you have them be provided by the same vendor.
A domain name is registered with a domain name registrar. There may be times when you might want to transfer a domain that you own from one registrar to another. For example, let's say that you purchased an domain name from GoDaddy.com and you purchased web hosting from Hostmonster.com. Now let say that you want to have Hostmonster handle your domain name instead of GoDaddy. This process of transfer the control of your domain from GoDaddy to Hostmonster is known as a "domain name transfer". You initiate this process from the "gaining registrar" (in this case Hostmonster). And you will need to unlock your domain and obtain the EPP code from the "losing registrar" (in this example, GoDaddy). This is an security measure to prevent unauthorized transfers. It is also standard that the losing registrar wait several days before releasing the registrar.
See the section Domain Name Transfer for the general steps. The whole process may take anywhere from a few days to a couple of weeks. Once transferred, the domain can not transfer to another registrar for another 60 days.
Domain name transfers can get a bit tricky, especially if you have an active site and emails on that domain name. So here are some references for you to study...
