Twittering using ethernet shield (Basics)

I tried using the twitter example on the Arduino website.
I entered my network info and userID & password only.
When I tried to upload it to the Arduino I get this error:
21: error: Twitter.h: No such file or directory In function 'void setup()':
Bad error line: -2

Line 21 is "int status = twitter.wait();"

Am I supposed to enter any more info?

void setup()
{
  Ethernet.begin(mac, ip, gateway, subnet);
  Serial.begin(9600);
  
  delay(1000);
  
  Serial.println("connecting ...");
  if (twitter.post(msg)) {
    int status = twitter.wait();
    if (status == 200) {
      Serial.println("OK.");
    } else {
      Serial.print("failed : code ");
      Serial.println(status);
    }

Thanks,

Alan