A very common question is: “How do i run a plugin/custom web application against a IFD deployment?”
You should use the below code:

CrmDiscoveryService disco = new CrmDiscoveryService();
disco.Url = “https://YOUR.IFD.URL/MSCRMServices/2007/SPLA/CrmDiscoveryService.asmx”;
RetrieveOrganizationsRequest orgRequest = new RetrieveOrganizationsRequest();
orgRequest.UserId = @”username”;
orgRequest.Password = “password”;
RetrieveOrganizationsResponse orgResponse = (RetrieveOrganizationsResponse)disco.Execute(orgRequest);
OrganizationDetail orgInfo = null;
foreach (OrganizationDetail orgdetail in orgResponse.OrganizationDetails)
{
if (orgdetail.OrganizationName.Equals(”OrgName”))
{
[...]