Wireshark : Wireshark is the world's foremost network protocol analyzer. It lets you see what's happening on your network at a microscopic level. It is the de fac...
HttpWatch : An HTTP Viewer and HTTP Sniffer for IE and Firefox
Its Continuous! : The tweet-sized continuous integration app for PHP development.
Sixpack : Sixpack is a language-agnostic ab testing framework
Sixpack makes it easy to run A/B tests across multiple web services written in different languages...
Vaurien is basically a Chaos Monkey for your TCP connections. Vaurien acts as a proxy between your application and any backend.
You can use it in your functional tests or even on a real deployment through the command-line.