Following code will help to Retrieve Cultures information from CRM into your Custom Web Application

                     // Retrieve the Locale IDs from the server.
                    RetrieveProvisionedLanguagesRequest reqLang = new RetrieveProvisionedLanguagesRequest();
                    RetrieveProvisionedLanguagesResponse resLang = (RetrieveProvisionedLanguagesResponse)crmService.Execute(reqLang);

                    // Create a CultureInfo array that represents the available languages.
                    System.Globalization.CultureInfo[] cultures =
                        new System.Globalization.CultureInfo[resLang.RetrieveProvisionedLanguages.Length];

                    for (int i = 0; i < resLang.RetrieveProvisionedLanguages.Length; i++)
                    {
                        cultures[i] = System.Globalization.CultureInfo.GetCultureInfo(resLang.RetrieveProvisionedLanguages[i]);
                    }

If you are looking for Globalization / Localization in Custom Web Application, have a look at

http://faisalmb.com/blog/post/2009/08/21/CRM-Globalization-Localization-in-Custom-Web-Application.aspx