simple Array question

Hi!
Could you tell me how to add something to an array?
I got an array like that:

string[] strings= new string[]{"a","b","c"};

now I want to add a "d" into the array, how?

Thanks very much. :)

Sorry, found out myself,
I use (pseudo-code):

using System.Collections;
ArrayList list = new ArrayList();
list.Add(something);