maintaining credentials for wcf binding over the life of my app
public class ProxyGenerator
{

    public string username;
    public SecureString password;
    public string endpoint;

    private TestingService.ServiceClient _proxy = null;

    public ProxyGenerator(string uname, SecureString pword)
    {
        username = uname;
        password = pword;

        endpoint = "insert endpoint here"

    }

    public TestingService.ServiceClient GetProxy()
    {
        _proxy = new ServiceClient(endpoint);
        _proxy.ClientCredentials.UserName.UserName = username;
        _proxy.ClientCredentials.UserName.Password = password;

        return _proxy;
    }
}