I read about stakeout.rb but read that it might not work on windows. Rather then waste time even trying I just ported it to PHP, and started to make it object oriented.
I have posted the code on devnetwork
Using this you can just work on your files, and keep PHPAutoTest open in another window. It will run your tests as needed. A couple features include customizable delay times, (sleep for as long as you need between file scans), customizable log levels, and ability to override various template methods such as runTests() (which is where you put your test runner invocation).