When changing DNS on a domain, it can take up to 24-48 hours for this change to propagate around the Internet. However, in practise this is usually alot less. Once you change your DNS, we recommend not visiting your domain for 2-3 hours and then retrying. You will usually find DNS has updated.
To see the DNS currently being used for your domain, please check www.intodns.com for a full technical breakdown of the DNS servers used and the zones within that DNS server.
Please note, for IE domains, changes are processed by the registry every odd hour, therefore there may be up to 2 hours of leadtime before your DNS change starts to take effect.