If you have a web site, I am sure you have heard of the term DNS used quite often. DNS stands for Domain Name Server/System/Service and it is a service that translates the alphanumeric characters in a domain name to an IP address. Since the Internet is based on IP Addresses, the DNS converts the address a user types, such as Microsoft.com, to its IP address (188.8.131.52).
When you are switching web hosting providers you generally have to change your DNS information from one host to another. This is a common practice and it is not quite difficult. In many cases the web hosting providers will actually change the DNS information for you if you are unable to do so.