Every iOS app should be thoroughly tested in a variety of network conditions, from a high-bandwidth WiFi connection down to a data connection with a single measly bar of Edge or GPRS coverage. Finding a good connection is usually the easiest, you're almost guaranteed to have one at work or home, but reliably testing an intermittent or poor connection is much harder. The obvious way to do this is to take note of coverage dead spots as you go about your day and return to those locations to test the app, but that can be time consuming and unreliable. However, if you have Max OS X 10.7 you can simulate any network connection without even leaving your desk.