Last week, I mentioned Apple's Network Link Conditioner as a testing tool.
Charles Web Debugging Proxy is a third-party debugging tool that is extremely important if you write apps that communicate with server APIs. When you start Charles, it automatically fires up a proxy server and modifies your OS X proxy server settings to point to it. Continue running your iOS app in the simulator and you will be able to monitor HTTP(s) requests in Charles.
There is a free trial available, so check it out.