CRM 4.0 Calling Web Service

public static CrmService GetCrmService(string orgName, string server)
{

CrmAuthenticationToken token = new CrmAuthenticationToken();
token.AuthenticationType = 0;
token.OrganizationName = orgName;

CrmService service = new CrmService();

service.Credentials = System.Net.CredentialCache.DefaultCredentials;
service.CrmAuthenticationTokenValue = token;
service.Url = string.Format("http://{0}/mscrmservices/2007/crmservice.asmx", server);
return service;

}