NSString *stringUrl = [NSString stringWithFormat:@"http://xxxxxxxxx/login.php?Username=%@&Password=%@",YouruserName, Yourpassword];

NSURL *url = [NSURL URLWithString:stringUrl];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response,
                                               NSData *data, NSError *connectionError)
{
      if (data.length > 0 && connectionError == nil)
      {
         NSDictionary *dicYourResponse = [NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];
      }
}];