string POST(string url, string entry, string username, string password)
{
string key = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes(username + ":" + password));
new System.Collections.Specialized.NameValueCollection();
WebClient client = new WebClient();
client.Headers.Add("Authorization", "Basic " + key);
client.Headers.Add("Content-Type", "application/atom+xml;type=entry");
return client.UploadString(url, "POST", entry);
}