Hi
after adding the web-reference to crmservice.asmx. u can use this code.
CrmAuthenticationToken token = new CrmAuthenticationToken();
// You can use enums.cs from the SDK\Helpers folder to get the enumeration for Active Directory authentication.
token.AuthenticationType = 0;
token.OrganizationName = "AdventureWorksCycle";
CrmService service = new CrmService();
service.Url = "http://<servername>:<port>/mscrmservices/2007/crmservice.asmx";
service.CrmAuthenticationTokenValue = token;
service.Credentials = System.Net.CredentialCache.DefaultCredentials;
// Create the contact object.
contact contactobj = new contact();
// Set the properties of the contactobj object.
contactobj.name = "Fourth Coffee";
contactobj.address1_line1 = "23 Market St.";
contactobj.address1_city = "Sammamish";
contactobj.address1_stateorprovince = "MT";
contactobj.address1_postalcode = "99999";
contactobj.donotbulkemail = new CrmBoolean();
contactobj.donotbulkemail.Value = true;
// set the contact parent customer id
contactobj.parentcustomerid = new Customer();
contactobj.parentcustomerid.type = EntityName.account.ToString();
contactobj.parentcustomerid.value = new Guid("account guid here");
Guid newID = service.Create(contactobj);