Create an SDL Tridion user trhough CoreService. Assumes having the Tridion Core Service Client DLL config as app.config

createTridionUser.cs

using System;
using System.ServiceModel;
using Tridion.ContentManager.CoreService.Client;

namespace CoreServiceSandbox
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var client = new CoreServiceClient("basicHttp_2013");
            try
            {
                Console.WriteLine("The current user is {0}\n", client.GetCurrentUser());

                UserData user = client.GetDefaultData(ItemType.User, null, new ReadOptions()) as UserData;
                Console.Write("Username (domain\\username): ");
                user.Title = Console.ReadLine();
                
                Console.Write("Full name: ");
                user.Description = Console.ReadLine();

                Console.Write("Is Tridion administrator: ");
                user.Privileges= ("yes".Equals(Console.ReadLine()) ? 1 : 0);

                Console.WriteLine("\nCreating user...");
                user = client.Create(user, new ReadOptions()) as UserData;
                Console.WriteLine("Created user {0}\n  Username {1}\n  Description {2}\n  Privleges {3}", user.Id, user.Title, user.Description, user.Privileges);
            }
            catch (FaultException<CoreServiceFault> e)
            {
                Console.WriteLine("Error; Core Service said: {0}; {1} ", e.Detail.ErrorCode, string.Join(", ", e.Detail.Messages));
            }
            catch (CommunicationException e)
            {
                Console.WriteLine("Error; Could not connect to the Core Service\n {0}\n {1}", e.Message, e.InnerException);
                client.Abort(); //The channel is aborted and the resources released.
            }
            catch (TimeoutException e)
            {
                Console.WriteLine("Error; Could not connect to the Core Service\n {0}\n {1}", e.Message, e.InnerException);
                client.Abort(); //The channel is aborted and the resources released.
            }
            catch (Exception e)
            {
                Console.WriteLine("Error; Could not connect to the Core Service\n {0}\n {1}", e.Message, e.InnerException);
            }

            Console.WriteLine("\nPress any key to continue...");
            Console.ReadKey();
        }
    }
}