ASI HTTP Request + JSON Sample

  
ASIHTTPRequest *req = [ASIHTTPRequest requestWithURL:URL];
    req.delegate = self;
    req.userInfo = [NSDictionary dictionaryWithObject:@"initialRequest" forKey:@"type"];
    NSData *body = [jsonString  dataUsingEncoding:NSUTF8StringEncoding];
    [req appendPostData:body];
    [req startSynchronous];