How can a PHP programmer go to robotics
I would suggest starting with an Arduino board and one of the many "Getting Started with Arduino"-style books out on the market. This is a very beginner-friendly way to get introduced to the world of embedded processors, device programming and simple circuit hacking. A few hours with an Arduino will also help you decide where your interests are really focused. (E.g. if you hate having to wire up an LED circuit just to see your program work, you probably want to focus on a more ready-made platform for robotics exploration. Whereas if you find the hardware tinkering appealing, you might want to move on to a very basic, bare-bones kit like the Parallax Stingray.)