Check the network is available or not + Iphone

checking of network
-(BOOL)checkNetworkConnection{
    NSString *connectingString=[[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://google.com"]];
    if ([connectingString length]==0) {
        NSLog(@"not connected");
        UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"Error" message:@"Network is not available " delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
        [alert release];
        netWork=YES;
    }
    else {
        netWork=NO;
    }
   
    [connectingString release];
    return netWork;
}