How to create user in active directory using c#.net web service

Hi,
if i am provide full right a user like (ABC), how i authenticate this user via using asp .net code, he(abc) is create new user in active directory.

hi,

when i try blew code

public string CreateUserAccount(string ldapPath, string userName,
string userPassword)
{
try
{
string oGUID = string.Empty;
string connectionPrefix = "LDAP://" + ldapPath;
DirectoryEntry dirEntry = new DirectoryEntry(connectionPrefix);
DirectoryEntry newUser = dirEntry.Children.Add
("CN=" + userName, "user");
newUser.Properties["samAccountName"].Value = userName;
newUser.CommitChanges();
oGUID = newUser.Guid.ToString();

newUser.Invoke("SetPassword", new object[] { userPassword });
newUser.CommitChanges();
dirEntry.Close();
newUser.Close();
}
catch (System.DirectoryServices.DirectoryServicesCOMException E)
{
//DoSomethingwith --> E.Message.ToString();

}
return oGUID;
}

i have facing issue in below line of code:-
newUser.Properties["samAccountName"].Value = userName;

this line giving compile time error("
Error 2 Non-invocable member 'System.DirectoryServices.DirectoryEntry.Properties' cannot be used like a method")

how to resolve this. please help me