Hi,

Below is the code that we could use to retrieve the GUIDs of all the members associated to a STATIC marketing list.

 private void GetAllMembers_Click(object sender, EventArgs e)
 {
 ArrayList memberGuids = new ArrayList();
 IOrganizationService orgService = GetOrganizationService();

PagingInfo pageInfo = new PagingInfo();
 pageInfo.Count = 5000;
 pageInfo.PageNumber = 1;

QueryByAttribute query = new QueryByAttribute("listmember");
 // pass the guid of the Static marketing list
 query.AddAttributeValue("listid", new Guid("2CA7881F-3EDA-E111-B988-00155D886334"));
 query.ColumnSet = new ColumnSet(true);
 EntityCollection entityCollection = orgService.RetrieveMultiple(query);

foreach (Entity entity in entityCollection.Entities)
 {
 memberGuids.Add(((EntityReference) entity.Attributes["entityid"]).Id);
 }

// if list contains more than 5000 records
 while (entityCollection.MoreRecords)
 {
 query.PageInfo.PageNumber += 1;
 query.PageInfo.PagingCookie = entityCollection.PagingCookie;
 entityCollection = orgService.RetrieveMultiple(query);

foreach (Entity entity in entityCollection.Entities)
 {
 memberGuids.Add(((EntityReference)entity.Attributes["entityid"]).Id);
 }
 }

}

public IOrganizationService GetOrganizationService()
 {
 Uri organizationUri = new Uri("http://servername/orgname/XRMServices/2011/Organization.svc");
 Uri homeRealmUri = null;
 ClientCredentials credentials = new ClientCredentials();
 credentials.Windows.ClientCredential = System.Net.CredentialCache.DefaultNetworkCredentials;
 OrganizationServiceProxy orgProxy = new OrganizationServiceProxy(organizationUri, homeRealmUri, credentials, null);
 IOrganizationService _service = (IOrganizationService)orgProxy;
 return _service;
 }

Hope it helps.