If you're like me, most of your work day is spent working on a local copy of a site. I have my local computer set up where each site lives at sitename.dev alias, but ran into problems when I realized I needed to test my site from my iPhone, but couldn't edit the hosts file there.
I spent WAY too long looking at Charles, Wireshark, and various other proxy related tools when a simple settings change solved my problem.
Connect your phone and computer to the same wireless network.
Go to your wireless networks settings page and look for 'HTTP Proxy' at the very bottom.
Type your computers local network IP address for Server, and 80 for the port.
You are now using your computer for HTTP requests including your custom hosts file.