Official Arduino WiFi Shield - Issues - Improvements - Call to action

Are you using IDE v1.0.5? Have you upgraded the firmware in your shield? Try this sketch to check your shield and firmware.
The firmware version should show 1.1.0. I set the serial baud to 9600, but I use 115200 here.

#include <WiFi.h>

// change to your WPA2 settings
char ssid[] = "mynetwork";     // the name of your network
char pass[] = "mypassphrase";  // your network password

int status = WL_IDLE_STATUS;     // the Wifi radio's status

void setup() {
  Serial.begin(9600);

  // disable SD SPI
  pinMode(4,OUTPUT);
  digitalWrite(4,HIGH);

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println(F("WiFi shield not present")); 
    // don't continue:
    while(true);
  } 

  // check firmware version
  Serial.print(F("Firmware version: "));
  Serial.println(WiFi.firmwareVersion());
  
 // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) { 
    Serial.print(F("Attempting to connect to SSID: "));
    Serial.println(ssid);
    status = WiFi.begin(ssid,pass);

    // wait 10 seconds for connection:
    delay(10000);
  }
   
  // you're connected now, so print out the data:
  Serial.print(F("You're connected to the network"));
  printCurrentNet();
  printWifiData();
}

void loop() {
}

void printCurrentNet() {
  // print the SSID of the network you're attached to:
  Serial.print(F("SSID: "));
  Serial.println(WiFi.SSID());

  // print the MAC address of the router you're attached to:
  byte bssid[6];
  WiFi.BSSID(bssid);    
  Serial.print(F("BSSID: "));
  Serial.print(bssid[5],HEX);
  Serial.print(F(":"));
  Serial.print(bssid[4],HEX);
  Serial.print(F(":"));
  Serial.print(bssid[3],HEX);
  Serial.print(F(":"));
  Serial.print(bssid[2],HEX);
  Serial.print(F(":"));
  Serial.print(bssid[1],HEX);
  Serial.print(F(":"));
  Serial.println(bssid[0],HEX);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print(F("signal strength (RSSI):"));
  Serial.println(rssi);

  // print the encryption type:
  byte encryption = WiFi.encryptionType();
  Serial.print(F("Encryption Type:"));
  Serial.println(encryption,HEX);
}

void printWifiData() {
  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
    Serial.print(F("IP Address: "));
  Serial.println(ip);
  Serial.println(ip);
  
  // print your MAC address:
  byte mac[6];  
  WiFi.macAddress(mac);
  Serial.print(F("MAC address: "));
  Serial.print(mac[5],HEX);
  Serial.print(F(":"));
  Serial.print(mac[4],HEX);
  Serial.print(F(":"));
  Serial.print(mac[3],HEX);
  Serial.print(F(":"));
  Serial.print(mac[2],HEX);
  Serial.print(F(":"));
  Serial.print(mac[1],HEX);
  Serial.print(F(":"));
  Serial.println(mac[0],HEX);
  
  // print your subnet mask:
  IPAddress subnet = WiFi.subnetMask();
  Serial.print(F("NetMask: "));
  Serial.println(subnet);

  // print your gateway address:
  IPAddress gateway = WiFi.gatewayIP();
  Serial.print(F("Gateway: "));
  Serial.println(gateway);
}