If you would like to view information on your domain name, such as contact information, domain name expiration date, current name servers, etc., you will need to do a whois search.  Please click a link below for a whois search engine:

http://www.whois.sc
http://www.networksolutions.com/whois/
http://www.internic.net/whois.html

Note: For domains with a double-extension, such as .co.uk, you will need to use the whois search engine at Network Solutions.

A search for Microsoft.com will reveal the following information:

Microsoft.com
Name Server: NS3.FSFT.NET
ICANN Registrar: TUCOWS INC.
Created: 1991-05-02
Expires: 2014-05-03
Status: REGISTER-LOCK

Administrative Contact:
Administrator, Domain  domains@microsoft.com
One Microsoft Way
Redmond, WA 98052
US
+1.4258828080

From the above results, you can tell who the registrar is (Tucows Inc.), when is was created (May 2, 1991), when it expires (May 3, 2014), if it's locked (Yes), the administrative email address (domains@microsoft.com), the name servers (NS3.FSFT.NET), etc..

If any information is incorrect on your search results, you will need to contact your current registrar and have them update this information.  If the registrar provides a web interface, you may be able to update this information on their website, depending if you have your username and password they provided.